Abstract

Terahertz (THz) optical materials containing polymeric materials have been useful for terahertz technologies. We investigated the THz optical properties of wood–plastic composites (WPCs), which are composed of polystyrene and wood powder, and their suitability as THz optical materials. We found that the refractive indexes and absorption coefficients of the WPCs increased with increasing wood powder content. WPCs are inexpensive and have tunable THz optical properties.

© 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

1. INTRODUCTION

Terahertz (THz) waves are electromagnetic waves that are typically considered to cover the frequencies from 100 GHz to 30 THz. THz technologies enable a wide variety of applications, including spectroscopy, imaging, and research on basic physics [1].

By using THz spectroscopy technology, we can extract chemical information about materials, since their vibrational energy levels are located at these frequencies. Applications of THz spectroscopy include investigating the properties of drugs [2], screening for explosive materials [3], and analyzing works of art [4,5]. By using a THz spectroscopy system based on attenuated total reflection (ATR) [6], we have been able to obtain THz information about materials easily and without any special skill. In the field of THz imaging, THz waves would be useful for nondestructive testing. Visualization of the internal state of visibly opaque black rubber objects by THz polarization spectroscopy was reported [7]. Recently, nondestructive imaging with a tiny THz semiconductor source that can be operated at room temperature was demonstrated [8]. Semiconductor devices are a promising tool for practical THz imaging.

These THz applications are made possible by THz optical components like lenses [9,10], absorbers [11,12], ATR prisms [6], diffusers [13], polarizers [14], and wave plates [15,16]. These optical components are made of THz optical materials. Although there are several THz optical materials, the number of suitable materials is limited compared with materials that work in general wavelength bands, such as visible light. Therefore, the technology to obtain the desired THz optical properties is required. A technology that can obtain the desired optical properties would be useful not only for fabricating optical components but also for fabricating antireflection (AR) coatings [17] having a graded-index profile by controlling the optical properties. Such a technology would also be useful for fabricating THz holographic materials [18]. We developed a THz material whose optical properties can be varied.

 figure: Fig. 1.

Fig. 1. Photographs of WPC samples. (a) WPC made of PS and (b) WPC made of PP.

Download Full Size | PPT Slide | PDF

Conventional THz optical materials include high-resistivity silicon, cyclic olefin polymer, and high-density polyethylene (HDPE) because they have high transparency for THz waves. Although high-resistivity silicon has low absorption for THz waves, high reflection loss at the incident and exit surfaces (Fresnel reflection) occurs because of its high refractive index. Also, with silicon, it is difficult to fabricate a desired shape by machining or molding.

The reflection loss of most polymeric materials is low because of their low refractive indices, and it is easy to fabricate various shapes by machining or molding [9,10]. In the case of polymeric materials, not only the raw material costs but also the production costs are lower than those of high-resistivity silicon. Another advantage of polymeric materials as THz optical materials is 3D printability. Recently, 3D printing technology has attracted attention. The THz optical properties of the following 3D printable materials have been investigated [19,20]: acrylonitrile butadiene styrene (ABS), polystyrene (PS), HDPE, polypropylene (PP), polylactic acid (PLA), nylon, bendlay, and cyclic olefin copolymer (TOPAS). Furthermore, several THz optical components fabricated by 3D printing technology have been demonstrated (e.g., lenses [21,22], lens arrays [23], waveguides [24,25], prisms [26], diffraction gratings [22], and Wollaston prisms [27]). Also, there are 3D printable materials formed of mixtures of polymers and powders including wood [28], carbon, and metal: in fact, a THz reflector was fabricated of a metallized 3D printable material including metal [29]. Because wood–plastic composites (WPCs) can be used for 3D printing filaments, investigating the THz optical properties of WPCs will contribute to advancing the fabrication of WPC optical components by 3D printing.

Thus, polymeric materials are widely used for THz optical components because they have several merits. To increase the variety of polymer materials that are suitable for THz optical components, we previously studied WPCs consisting of wood and PP as a THz optical material [30]. In the previous work, we investigated the THz optical properties of WPCs containing PP and confirmed their tolerance of humidity. However, available WPCs are not only made of PP. In this work, we investigated the THz optical properties of WPCs made of other materials. Furthermore, we performed multiple measurements on each sample and determined the error of the THz optical properties of the WPCs. Also, we evaluated the influence on the THz optical properties when we changed the relationship between the sample and the polarization direction of the incident THz waves.

2. EXPERIMENT

Commonly used materials for WPCs include PP, PS, and ABS. However, ABS is not suitable for THz materials because it has high THz absorption. PS is easier to form into various shapes by machining compared with PP. In this study, we investigated the optical properties of WPCs made of PS. We prepared WPC samples having different wood powder contents, namely 0, 10, 20, 30, 40, and 50 wt%. In the case of PS, molding became difficult when the wood powder content exceeded 50 wt%.

For comparison, we also prepared WPCs made of PP samples having different wood powder contents, namely, 0, 10, 20, 30, 40, 50, and 60 wt%. The wood powders in the WPCs were passed through a mesh filter with a mesh size of approximately 180 µm. The WPC samples had a length, $l$, of 62 mm, a width, $w$, of 10 mm, and a thickness, $t$, of 3 mm. Figure 1 shows a photograph of the WPC samples. All samples were composed of only wood powder and polymer material (PS or PP), without any additives, because additives may exhibit absorption of THz waves.

First, the samples were dried in a vacuum drier at 60°C for 1 week to a moisture content of 0%. After the drying process, the samples were kept in the laboratory (room temperature 25°C, humidity 40%). Then, we measured the samples with THz time-domain spectroscopy. Tables 1 and 2 show the water content of each sample immediately before the measurements. The water content of all the samples was less than 1.5%. A THz beam was focused at the sample position. The THz focused beam waist was approximately 1.5 mm (FWHM). THz waves for the measurement were linearly polarized. Figure 2 shows the relationship between the polarization of THz waves and the direction of the samples. Basically, we obtained the THz optical properties from the results of transmission measurements with vertically polarized THz waves, as shown in Fig. 2(a).

Tables Icon

Table 1. Water Contents of Samples Having Different Wood Powder Contents (PS)

Tables Icon

Table 2. Water Contents of Samples Having Different Wood Powder Contents (PP)

 figure: Fig. 2.

Fig. 2. Schematic representation of the transmission measurement of WPC samples. (a) Vertical polarization; (b) horizontal polarization.

Download Full Size | PPT Slide | PDF

3. RESULTS AND DISCUSSION

A. THz Optical Properties of WPCs (PP)

First, we obtained the THz properties of the WPCs made of PP. To confirm the uncertainty of the measurements, including errors of the measurement points in the samples, we measured the THz spectra of the samples 3 times. Figure 3 shows the average refractive indices and absorption coefficients of WPCs made of PP at frequencies between 0.25 and 2 THz, with error bars (standard deviation). Part of the data for the 50 and 60 wt% samples is not shown because the values could not be measured due to their high absorption. We found that the refractive index increased as the wood powder content was increased. The samples showed low dispersion. As shown in Fig. 3(b), the absorption coefficient increased as the wood powder content was increased. We found that the optical properties mostly did not overlap between the samples having different wood powder contents. Although the particle size of the wood powder and the water contents were slightly different from those in Ref. [30], we found that the THz properties were in good agreement with the results in Ref. [30].

 figure: Fig. 3.

Fig. 3. Optical properties of several WPCs having different wood powder contents (PP). (a) Refractive index and (b) absorption coefficient.

Download Full Size | PPT Slide | PDF

 figure: Fig. 4.

Fig. 4. Optical properties of several WPCs having different wood powder contents (PS). (a) Refractive index and (b) absorption coefficient.

Download Full Size | PPT Slide | PDF

B. THz Optical Properties of WPCs (PS)

We obtained the THz properties of WPCs made of PS. Figure 4 shows the average refractive indices and absorption coefficients of WPCs made of PS at frequencies between 0.25 and 2 THz with error bars. Part of the data for the 30, 40, and 50 wt% samples is not shown because the values could not be measured due to their high absorption. We found that the refractive index increased as the wood powder content was increased. The samples showed low dispersion, like the WPCs made of PP. As shown in Fig. 4(b), the absorption coefficient increased as the wood powder content was increased.

 figure: Fig. 5.

Fig. 5. Photograph of wood powder obtained by laser scanning microscopy.

Download Full Size | PPT Slide | PDF

 figure: Fig. 6.

Fig. 6. Optical properties of several WPCs having different wood powder contents (PP) with vertical polarization (see above) and horizontal polarization: (a) refractive index, and (b) absorption coefficient.

Download Full Size | PPT Slide | PDF

 figure: Fig. 7.

Fig. 7. Optical properties of several WPCs having different wood powder contents (PS) with vertical polarization (see above) and horizontal polarization: (a) refractive index, and (b) absorption coefficient.

Download Full Size | PPT Slide | PDF

Although we consider that a high absorption coefficient is an advantage when we apply this material to attenuation filters or diffusers, a high absorption coefficient would be a disadvantage if one is concerned about transmission losses. In the case of the WPCs (PP) having a wood content of 40 wt% and below and the WPCs (PS) having a wood content of 30 wt% and below, the absorption coefficients were under ${20}\,\,{{\rm cm}^{ - 1}}$ below 1.5 THz. Although these absorption coefficients were lower than those of nylon, PLA, and polyvinyl alcohol, the values were not low. On the other hand, below 500 GHz, the absorption coefficients of all the samples that we examined were below ${10}\,\,{{\rm cm}^{ - 1}}$. Therefore, THz optical components made of WPCs would be useful in the sub-THz range. Recently, sub-THz light sources have become compact and easy to handle and exhibit high emission powers. THz waves in this range have high transmittance in various materials, and sub-THz waves are expected to be useful for nondestructive testing and security applications. We consider that our WPC is suitable for sub-THz applications.

C. Polarization-Dependency of THz Optical Properties of WPCs

Figure 5 shows a photograph of wood powder obtained by laser scanning microscopy. Most wood powder particles have short cylinder-like shapes. If the particles are collectively in the same direction in the matrix due to the injection molding conditions of the WPC sample, the THz optical properties of the WPC would exhibit polarization dependency. To confirm the polarization dependency of the WPCs, we measured the optical properties with vertical polarization [Fig. 2(a)] and horizontal polarization [Fig. 2(b)]. Figures 6 and 7 show the THz optical properties obtained with vertical polarization and horizontal polarization, respectively.

As shown in Figs. 6 and 7, there were no significant differences between the absorption coefficient with vertical polarization and that with horizontal polarization, but the refractive index with horizontal polarization was slightly higher than that with vertical polarization. This result suggests the possibility that the orientation of the wood particles in the WPC is not completely random. However, we cannot conclude that there were significant differences between the vertical polarization and horizontal polarization, considering the overlapping of the error bars.

For further consideration, we should decrease the experimental error by improving the uniformity of the distribution of wood particles in the WPC. Commonly, a dispersant is used to improve the uniformity of wood particles in WPCs. In this work, we did not use a dispersant because the dispersant may exhibit absorption of THz waves. We will attempt to make a more uniform WPC sample and improve the experimental error in future work. Also, information about the actual condition of the wood particles in the WPCs (distribution of wood powder, orientation of wood powder particles) will help to explain the behavior of the THz optical properties (polarization-dependent or polarization-independent). Therefore, we plan to obtain information about the condition of the wood powder in WPCs by using microfocus x-ray computed tomography (CT) in future work.

4. CONCLUSIONS

We investigated the THz optical properties of various WPCs made of PS samples having wood powder contents in the range from 0 wt% to 50 wt% and their suitability as THz optical materials. The refractive indexes and absorption coefficients were changed by changing the wood powder contents. Therefore, THz materials with the desired refractive index can be obtained by adjusting the wood powder content. This is one of the advantages of WPCs. Although originally we had proposed WPCs made of PP as THz optical materials, we found that WPCs made of PS could also be used for THz materials. Compared with PP, PS is easier to form into various shapes by machining. Thus, the variety of polymer material for THz optical components can be increased. Although we evaluated the influence on the THz optical properties of WPCs by changing the relationship between the sample and the THz polarization direction, we could not conclude that they have polarization-dependence or polarization-independence because of overlapping of the error bars. To examine this issue in more depth, we plan to make more uniform WPC samples and decrease the experimental error.

The uses of WPCs include not only refractive optical components such as lenses or diffraction gratings but also optical components formed of absorbing or scattering materials, such as attenuation filters and diffusers. The THz beam from an optical source such as a quantum cascade laser or optically pumped THz gas laser has high coherency; therefore, when obtaining THz images with these sources, speckle patterns or fringe patterns often appear in the THz images. In the visible light region, the coherency of an optical beam can be decreased by using a diffuser to prevent such speckle patterns or fringe patterns. In the THz range, a THz diffuser could be effective in decreasing coherency. A diffuser made of WPC would be useful for THz applications.

Also, the absorption coefficients of samples, including wood powder, increased with frequency. In the case of a material including powder whose diameter is about 50–200 µm, the THz absorption spectrum is affected by scattering; the THz absorption decreases as the powder particle size is decreased [31]. We consider that the observed high absorption coefficient of WPCs in the high-frequency region was also caused by scattering. In this work, we used WPC samples containing wood powders that were passed through a mesh filter with a mesh size of about 180 µm. By using wood powders with a smaller particle size in WPCs, the absorption coefficient could be decreased in the high-frequency region.

Acknowledgment

The authors thank T. Hara, H. Nakagawa, and H. Takahashi of Hamamatsu Photonics, K. K.

Disclosures

The authors declare no conflict of interest.

REFERENCES

1. M. Tonouchi, “Cutting-edge terahertz technology,” Nat. Photonics 1, 97–105 (2007). [CrossRef]  

2. G. Takebe, Y. Kawada, K. Akiyama, H. Takahashi, H. Takamoto, and M. Hiramatsu, “Evaluation of drug crystallinity in aqueous suspension using terahertz time-domain attenuated total reflection spectroscopy,” J. Pharm. Sci. 102, 4065–4071 (2013). [CrossRef]  

3. N. Greenall, A. Valavanis, H. J. Desai, D. O. Acheampong, L. H. Li, J. E. Cunningham, A. G. Davies, E. H. Linfield, and A. D. Burnett, “The development of a Semtex-H simulant for terahertz spectroscopy,” J. Infrared Millim. Terahertz Waves 38, 325–338 (2017). [CrossRef]  

4. A. D. Squires, M. Kelly, and R. A. Lewis, “Terahertz analysis of quinacridone pigments,” J. Infrared Millim. Terahertz Waves 38, 314–324 (2017). [CrossRef]  

5. A. D. Squires and R. A. Lewis, “Terahertz analysis of phthalocyanine pigments,” J. Infrared Millim. Terahertz Waves 40, 738–751 (2019). [CrossRef]  

6. A. Nakanishi, Y. Kawada, T. Yasuda, K. Akiyama, and H. Takahashi, “Terahertz time domain attenuated total reflection spectroscopy with an integrated prism system,” Rev. Sci. Instrum. 83, 033103 (2012). [CrossRef]  

7. M. Okano and S. Watanabe, “Internal status of visibly opaque black rubbers investigated by terahertz polarization spectroscopy: fundamentals and applications,” Polymers 11, 9 (2019). [CrossRef]  

8. A. Nakanishi, K. Fujita, K. Horita, and H. Takahashi, “Terahertz imaging with room-temperature terahertz difference-frequency quantum-cascade laser sources,” Opt. Express 27, 1884–1893 (2019). [CrossRef]  

9. B. Scherger, S. Wietzke, M. Scheller, N. Vieweg, M. Wichmann, M. Koch, and K. Wiesauer, “Characterization of micro-powders for fabrication of compression molded THz lenses,” J. Infrared Millim. Terahertz Waves 32, 943–951 (2011). [CrossRef]  

10. M. Wichmann, A. S. Mondol, N. Kocic, S. Lippert, T. Probst, M. Schwerdtfeger, S. Schumann, T. Hochrein, P. Heidemeyer, M. Bastian, G. Bastian, and M. Koch, “Terahertz plastic compound lenses,” Appl. Opt. 52, 4186–4191 (2013). [CrossRef]  

11. G. Xu, J. Zhang, X. Zang, O. Sugihara, H. Zhao, and B. Cai, “0.1–20 THz ultra-broadband perfect absorber via a flat multi-layer structure,” Opt. Express 24, 23177–23185 (2016). [CrossRef]  

12. D.-S. Kim, D.-H. Kim, S. Hwang, and J.-H. Jang, “Broadband terahertz absorber realized by self-assembled multilayer glass spheres,” Opt. Express 20, 13566–13572 (2012). [CrossRef]  

13. S. Islam, J. Stiens, G. Poesen, I. Jaeger, W. D. Raedt, and R. Vounckx, “Periodicity perturbed grounded frequency selective surface arrays as millimeter wave random phase coherence destroying diffusers,” J. Infrared Millim. Terahertz Waves 31, 641–648 (2010). [CrossRef]  

14. A. Wojdyla and G. Gallot, “Brewster’s angle silicon wafer terahertz linear polarizer,” Opt. Express 19, 14099–14107 (2011). [CrossRef]  

15. R. Xia, X. Jing, X. Gui, Y. Tian, and Z. Hong, “Broadband terahertz half-wave plate based on anisotropic polarization conversion metamaterials,” Opt. Mater. Express 7, 977–988 (2017). [CrossRef]  

16. L. Wang, S. Ge, W. Hu, M. Nakajima, and Y. Lu, “Tunable reflective liquid crystal terahertz waveplates,” Opt. Mater. Express 7, 2023–2029 (2017). [CrossRef]  

17. B. Cai, H. Chen, G. Xu, H. Zhao, and O. Sugihara, “Ultra-broadband THz antireflective coating with polymer composites,” Polymers 9, 574 (2017). [CrossRef]  

18. W.-R. Ng, D. R. Golish, H. Xin, and M. E. Gehm, “Direct rapid-prototyping fabrication of computer-generated volume holograms in the millimeter-wave and terahertz regime,” Opt. Express 22, 3349–3355 (2014). [CrossRef]  

19. S. F. Busch, M. Weidenbach, M. Fey, F. Schäfer, T. Probst, and M. Koch, “Optical properties of 3D printable plastics in the THz regime and their application for 3D printed THz optics,” J. Infrared Millim. Terahertz Waves 35, 993–997 (2014). [CrossRef]  

20. A. D. Squires and R. A. Lewis, “Feasibility and characterization of common and exotic filaments for use in 3D printed terahertz device,” J. Infrared Millim. Terahertz Waves 39, 614–635 (2018). [CrossRef]  

21. S. F. Busch, M. Weidenbach, J. C. Balzer, and M. Koch, “THz optics 3D printed with TOPAS,” J. Infrared Millim. Terahertz Waves 37, 303–307 (2016). [CrossRef]  

22. A. D. Squires, E. Constable, and R. A. Lewis, “3D printed terahertz diffraction grating and lenses,” J. Infrared Millim. Terahertz Waves 36, 72–80 (2015). [CrossRef]  

23. K. Szkudlarek, M. Sypek, G. Cywiński, J. Suszek, P. Zagrajek, A. Feduniewicz-Żmuda, I. Yahniuk, S. Yatsunenko, A. Nowakowska-Siwińska, D. Coquillat, D. B. But, M. Rachoń, K. Węgrzyńska, C. Skierbiszewski, and W. Knap, “Terahertz 3D printed diffractive lens matrices for field-effect transistor detector focal plane arrays,” Opt. Express 24, 20119–20131 (2016). [CrossRef]  

24. J. Yang, J. Zhao, C. Gong, H. Tian, L. Sun, P. Chen, L. Lin, and W. Liu, “3D printed low-loss THz waveguide based on Kagome photonic crystal structure,” Opt. Express 24, 22454–22460 (2016). [CrossRef]  

25. D. W. Vogt and R. Leonhardt, “3D-printed broadband dielectric tube terahertz waveguide with anti-reflection structure,” J. Infrared Millim. Terahertz Waves 37, 1086–1095 (2016). [CrossRef]  

26. S. F. Busch, E. Castro-Camus, F. Beltran-Mejia, J. C. Balzer, and M. Koch, “3D printed prisms with tunable dispersion for the THz frequency range,” J. Infrared Millim. Terahertz Waves 39, 553–560 (2018). [CrossRef]  

27. A. I. Hernandez-Serrano and E. Castro-Camus, “Quasi-Wollaston-prism for terahertz frequencies fabricated by 3D printing,” J. Infrared Millim. Terahertz Waves 38, 567–573 (2017). [CrossRef]  

28. M. Kariz, M. Sernek, M. Obućina, and M. K. Kuzman, “Effect of wood content in FDM filament on properties of 3D printed parts,” Mater. Today Commun. 14, 135–140 (2018). [CrossRef]  

29. J. A. Colla, R. E. M. Vickers, M. Nancarrow, and R. A. Lewis, “3D printing metallized plastics as terahertz reflectors,” J. Infrared Millim. Terahertz Waves 40, 752–762 (2019). [CrossRef]  

30. A. Nakanishi and H. Takahashi, “Terahertz optical material based on wood-plastic composites,” Opt. Mater. Express 8, 3653–3658 (2018). [CrossRef]  

31. Y. C. Shen, P. F. Taday, and M. Pepper, “Elimination of scattering effects in spectral measurement of granulated materials using terahertz pulsed spectroscopy,” Appl. Phys. Lett. 92, 051103 (2008). [CrossRef]  

References

  • View by:
  • |
  • |
  • |

  1. M. Tonouchi, “Cutting-edge terahertz technology,” Nat. Photonics 1, 97–105 (2007).
    [Crossref]
  2. G. Takebe, Y. Kawada, K. Akiyama, H. Takahashi, H. Takamoto, and M. Hiramatsu, “Evaluation of drug crystallinity in aqueous suspension using terahertz time-domain attenuated total reflection spectroscopy,” J. Pharm. Sci. 102, 4065–4071 (2013).
    [Crossref]
  3. N. Greenall, A. Valavanis, H. J. Desai, D. O. Acheampong, L. H. Li, J. E. Cunningham, A. G. Davies, E. H. Linfield, and A. D. Burnett, “The development of a Semtex-H simulant for terahertz spectroscopy,” J. Infrared Millim. Terahertz Waves 38, 325–338 (2017).
    [Crossref]
  4. A. D. Squires, M. Kelly, and R. A. Lewis, “Terahertz analysis of quinacridone pigments,” J. Infrared Millim. Terahertz Waves 38, 314–324 (2017).
    [Crossref]
  5. A. D. Squires and R. A. Lewis, “Terahertz analysis of phthalocyanine pigments,” J. Infrared Millim. Terahertz Waves 40, 738–751 (2019).
    [Crossref]
  6. A. Nakanishi, Y. Kawada, T. Yasuda, K. Akiyama, and H. Takahashi, “Terahertz time domain attenuated total reflection spectroscopy with an integrated prism system,” Rev. Sci. Instrum. 83, 033103 (2012).
    [Crossref]
  7. M. Okano and S. Watanabe, “Internal status of visibly opaque black rubbers investigated by terahertz polarization spectroscopy: fundamentals and applications,” Polymers 11, 9 (2019).
    [Crossref]
  8. A. Nakanishi, K. Fujita, K. Horita, and H. Takahashi, “Terahertz imaging with room-temperature terahertz difference-frequency quantum-cascade laser sources,” Opt. Express 27, 1884–1893 (2019).
    [Crossref]
  9. B. Scherger, S. Wietzke, M. Scheller, N. Vieweg, M. Wichmann, M. Koch, and K. Wiesauer, “Characterization of micro-powders for fabrication of compression molded THz lenses,” J. Infrared Millim. Terahertz Waves 32, 943–951 (2011).
    [Crossref]
  10. M. Wichmann, A. S. Mondol, N. Kocic, S. Lippert, T. Probst, M. Schwerdtfeger, S. Schumann, T. Hochrein, P. Heidemeyer, M. Bastian, G. Bastian, and M. Koch, “Terahertz plastic compound lenses,” Appl. Opt. 52, 4186–4191 (2013).
    [Crossref]
  11. G. Xu, J. Zhang, X. Zang, O. Sugihara, H. Zhao, and B. Cai, “0.1–20 THz ultra-broadband perfect absorber via a flat multi-layer structure,” Opt. Express 24, 23177–23185 (2016).
    [Crossref]
  12. D.-S. Kim, D.-H. Kim, S. Hwang, and J.-H. Jang, “Broadband terahertz absorber realized by self-assembled multilayer glass spheres,” Opt. Express 20, 13566–13572 (2012).
    [Crossref]
  13. S. Islam, J. Stiens, G. Poesen, I. Jaeger, W. D. Raedt, and R. Vounckx, “Periodicity perturbed grounded frequency selective surface arrays as millimeter wave random phase coherence destroying diffusers,” J. Infrared Millim. Terahertz Waves 31, 641–648 (2010).
    [Crossref]
  14. A. Wojdyla and G. Gallot, “Brewster’s angle silicon wafer terahertz linear polarizer,” Opt. Express 19, 14099–14107 (2011).
    [Crossref]
  15. R. Xia, X. Jing, X. Gui, Y. Tian, and Z. Hong, “Broadband terahertz half-wave plate based on anisotropic polarization conversion metamaterials,” Opt. Mater. Express 7, 977–988 (2017).
    [Crossref]
  16. L. Wang, S. Ge, W. Hu, M. Nakajima, and Y. Lu, “Tunable reflective liquid crystal terahertz waveplates,” Opt. Mater. Express 7, 2023–2029 (2017).
    [Crossref]
  17. B. Cai, H. Chen, G. Xu, H. Zhao, and O. Sugihara, “Ultra-broadband THz antireflective coating with polymer composites,” Polymers 9, 574 (2017).
    [Crossref]
  18. W.-R. Ng, D. R. Golish, H. Xin, and M. E. Gehm, “Direct rapid-prototyping fabrication of computer-generated volume holograms in the millimeter-wave and terahertz regime,” Opt. Express 22, 3349–3355 (2014).
    [Crossref]
  19. S. F. Busch, M. Weidenbach, M. Fey, F. Schäfer, T. Probst, and M. Koch, “Optical properties of 3D printable plastics in the THz regime and their application for 3D printed THz optics,” J. Infrared Millim. Terahertz Waves 35, 993–997 (2014).
    [Crossref]
  20. A. D. Squires and R. A. Lewis, “Feasibility and characterization of common and exotic filaments for use in 3D printed terahertz device,” J. Infrared Millim. Terahertz Waves 39, 614–635 (2018).
    [Crossref]
  21. S. F. Busch, M. Weidenbach, J. C. Balzer, and M. Koch, “THz optics 3D printed with TOPAS,” J. Infrared Millim. Terahertz Waves 37, 303–307 (2016).
    [Crossref]
  22. A. D. Squires, E. Constable, and R. A. Lewis, “3D printed terahertz diffraction grating and lenses,” J. Infrared Millim. Terahertz Waves 36, 72–80 (2015).
    [Crossref]
  23. K. Szkudlarek, M. Sypek, G. Cywiński, J. Suszek, P. Zagrajek, A. Feduniewicz-Żmuda, I. Yahniuk, S. Yatsunenko, A. Nowakowska-Siwińska, D. Coquillat, D. B. But, M. Rachoń, K. Węgrzyńska, C. Skierbiszewski, and W. Knap, “Terahertz 3D printed diffractive lens matrices for field-effect transistor detector focal plane arrays,” Opt. Express 24, 20119–20131 (2016).
    [Crossref]
  24. J. Yang, J. Zhao, C. Gong, H. Tian, L. Sun, P. Chen, L. Lin, and W. Liu, “3D printed low-loss THz waveguide based on Kagome photonic crystal structure,” Opt. Express 24, 22454–22460 (2016).
    [Crossref]
  25. D. W. Vogt and R. Leonhardt, “3D-printed broadband dielectric tube terahertz waveguide with anti-reflection structure,” J. Infrared Millim. Terahertz Waves 37, 1086–1095 (2016).
    [Crossref]
  26. S. F. Busch, E. Castro-Camus, F. Beltran-Mejia, J. C. Balzer, and M. Koch, “3D printed prisms with tunable dispersion for the THz frequency range,” J. Infrared Millim. Terahertz Waves 39, 553–560 (2018).
    [Crossref]
  27. A. I. Hernandez-Serrano and E. Castro-Camus, “Quasi-Wollaston-prism for terahertz frequencies fabricated by 3D printing,” J. Infrared Millim. Terahertz Waves 38, 567–573 (2017).
    [Crossref]
  28. M. Kariz, M. Sernek, M. Obućina, and M. K. Kuzman, “Effect of wood content in FDM filament on properties of 3D printed parts,” Mater. Today Commun. 14, 135–140 (2018).
    [Crossref]
  29. J. A. Colla, R. E. M. Vickers, M. Nancarrow, and R. A. Lewis, “3D printing metallized plastics as terahertz reflectors,” J. Infrared Millim. Terahertz Waves 40, 752–762 (2019).
    [Crossref]
  30. A. Nakanishi and H. Takahashi, “Terahertz optical material based on wood-plastic composites,” Opt. Mater. Express 8, 3653–3658 (2018).
    [Crossref]
  31. Y. C. Shen, P. F. Taday, and M. Pepper, “Elimination of scattering effects in spectral measurement of granulated materials using terahertz pulsed spectroscopy,” Appl. Phys. Lett. 92, 051103 (2008).
    [Crossref]

2019 (4)

A. D. Squires and R. A. Lewis, “Terahertz analysis of phthalocyanine pigments,” J. Infrared Millim. Terahertz Waves 40, 738–751 (2019).
[Crossref]

M. Okano and S. Watanabe, “Internal status of visibly opaque black rubbers investigated by terahertz polarization spectroscopy: fundamentals and applications,” Polymers 11, 9 (2019).
[Crossref]

A. Nakanishi, K. Fujita, K. Horita, and H. Takahashi, “Terahertz imaging with room-temperature terahertz difference-frequency quantum-cascade laser sources,” Opt. Express 27, 1884–1893 (2019).
[Crossref]

J. A. Colla, R. E. M. Vickers, M. Nancarrow, and R. A. Lewis, “3D printing metallized plastics as terahertz reflectors,” J. Infrared Millim. Terahertz Waves 40, 752–762 (2019).
[Crossref]

2018 (4)

A. Nakanishi and H. Takahashi, “Terahertz optical material based on wood-plastic composites,” Opt. Mater. Express 8, 3653–3658 (2018).
[Crossref]

S. F. Busch, E. Castro-Camus, F. Beltran-Mejia, J. C. Balzer, and M. Koch, “3D printed prisms with tunable dispersion for the THz frequency range,” J. Infrared Millim. Terahertz Waves 39, 553–560 (2018).
[Crossref]

A. D. Squires and R. A. Lewis, “Feasibility and characterization of common and exotic filaments for use in 3D printed terahertz device,” J. Infrared Millim. Terahertz Waves 39, 614–635 (2018).
[Crossref]

M. Kariz, M. Sernek, M. Obućina, and M. K. Kuzman, “Effect of wood content in FDM filament on properties of 3D printed parts,” Mater. Today Commun. 14, 135–140 (2018).
[Crossref]

2017 (6)

A. I. Hernandez-Serrano and E. Castro-Camus, “Quasi-Wollaston-prism for terahertz frequencies fabricated by 3D printing,” J. Infrared Millim. Terahertz Waves 38, 567–573 (2017).
[Crossref]

N. Greenall, A. Valavanis, H. J. Desai, D. O. Acheampong, L. H. Li, J. E. Cunningham, A. G. Davies, E. H. Linfield, and A. D. Burnett, “The development of a Semtex-H simulant for terahertz spectroscopy,” J. Infrared Millim. Terahertz Waves 38, 325–338 (2017).
[Crossref]

A. D. Squires, M. Kelly, and R. A. Lewis, “Terahertz analysis of quinacridone pigments,” J. Infrared Millim. Terahertz Waves 38, 314–324 (2017).
[Crossref]

R. Xia, X. Jing, X. Gui, Y. Tian, and Z. Hong, “Broadband terahertz half-wave plate based on anisotropic polarization conversion metamaterials,” Opt. Mater. Express 7, 977–988 (2017).
[Crossref]

L. Wang, S. Ge, W. Hu, M. Nakajima, and Y. Lu, “Tunable reflective liquid crystal terahertz waveplates,” Opt. Mater. Express 7, 2023–2029 (2017).
[Crossref]

B. Cai, H. Chen, G. Xu, H. Zhao, and O. Sugihara, “Ultra-broadband THz antireflective coating with polymer composites,” Polymers 9, 574 (2017).
[Crossref]

2016 (5)

2015 (1)

A. D. Squires, E. Constable, and R. A. Lewis, “3D printed terahertz diffraction grating and lenses,” J. Infrared Millim. Terahertz Waves 36, 72–80 (2015).
[Crossref]

2014 (2)

W.-R. Ng, D. R. Golish, H. Xin, and M. E. Gehm, “Direct rapid-prototyping fabrication of computer-generated volume holograms in the millimeter-wave and terahertz regime,” Opt. Express 22, 3349–3355 (2014).
[Crossref]

S. F. Busch, M. Weidenbach, M. Fey, F. Schäfer, T. Probst, and M. Koch, “Optical properties of 3D printable plastics in the THz regime and their application for 3D printed THz optics,” J. Infrared Millim. Terahertz Waves 35, 993–997 (2014).
[Crossref]

2013 (2)

M. Wichmann, A. S. Mondol, N. Kocic, S. Lippert, T. Probst, M. Schwerdtfeger, S. Schumann, T. Hochrein, P. Heidemeyer, M. Bastian, G. Bastian, and M. Koch, “Terahertz plastic compound lenses,” Appl. Opt. 52, 4186–4191 (2013).
[Crossref]

G. Takebe, Y. Kawada, K. Akiyama, H. Takahashi, H. Takamoto, and M. Hiramatsu, “Evaluation of drug crystallinity in aqueous suspension using terahertz time-domain attenuated total reflection spectroscopy,” J. Pharm. Sci. 102, 4065–4071 (2013).
[Crossref]

2012 (2)

A. Nakanishi, Y. Kawada, T. Yasuda, K. Akiyama, and H. Takahashi, “Terahertz time domain attenuated total reflection spectroscopy with an integrated prism system,” Rev. Sci. Instrum. 83, 033103 (2012).
[Crossref]

D.-S. Kim, D.-H. Kim, S. Hwang, and J.-H. Jang, “Broadband terahertz absorber realized by self-assembled multilayer glass spheres,” Opt. Express 20, 13566–13572 (2012).
[Crossref]

2011 (2)

A. Wojdyla and G. Gallot, “Brewster’s angle silicon wafer terahertz linear polarizer,” Opt. Express 19, 14099–14107 (2011).
[Crossref]

B. Scherger, S. Wietzke, M. Scheller, N. Vieweg, M. Wichmann, M. Koch, and K. Wiesauer, “Characterization of micro-powders for fabrication of compression molded THz lenses,” J. Infrared Millim. Terahertz Waves 32, 943–951 (2011).
[Crossref]

2010 (1)

S. Islam, J. Stiens, G. Poesen, I. Jaeger, W. D. Raedt, and R. Vounckx, “Periodicity perturbed grounded frequency selective surface arrays as millimeter wave random phase coherence destroying diffusers,” J. Infrared Millim. Terahertz Waves 31, 641–648 (2010).
[Crossref]

2008 (1)

Y. C. Shen, P. F. Taday, and M. Pepper, “Elimination of scattering effects in spectral measurement of granulated materials using terahertz pulsed spectroscopy,” Appl. Phys. Lett. 92, 051103 (2008).
[Crossref]

2007 (1)

M. Tonouchi, “Cutting-edge terahertz technology,” Nat. Photonics 1, 97–105 (2007).
[Crossref]

Acheampong, D. O.

N. Greenall, A. Valavanis, H. J. Desai, D. O. Acheampong, L. H. Li, J. E. Cunningham, A. G. Davies, E. H. Linfield, and A. D. Burnett, “The development of a Semtex-H simulant for terahertz spectroscopy,” J. Infrared Millim. Terahertz Waves 38, 325–338 (2017).
[Crossref]

Akiyama, K.

G. Takebe, Y. Kawada, K. Akiyama, H. Takahashi, H. Takamoto, and M. Hiramatsu, “Evaluation of drug crystallinity in aqueous suspension using terahertz time-domain attenuated total reflection spectroscopy,” J. Pharm. Sci. 102, 4065–4071 (2013).
[Crossref]

A. Nakanishi, Y. Kawada, T. Yasuda, K. Akiyama, and H. Takahashi, “Terahertz time domain attenuated total reflection spectroscopy with an integrated prism system,” Rev. Sci. Instrum. 83, 033103 (2012).
[Crossref]

Balzer, J. C.

S. F. Busch, E. Castro-Camus, F. Beltran-Mejia, J. C. Balzer, and M. Koch, “3D printed prisms with tunable dispersion for the THz frequency range,” J. Infrared Millim. Terahertz Waves 39, 553–560 (2018).
[Crossref]

S. F. Busch, M. Weidenbach, J. C. Balzer, and M. Koch, “THz optics 3D printed with TOPAS,” J. Infrared Millim. Terahertz Waves 37, 303–307 (2016).
[Crossref]

Bastian, G.

Bastian, M.

Beltran-Mejia, F.

S. F. Busch, E. Castro-Camus, F. Beltran-Mejia, J. C. Balzer, and M. Koch, “3D printed prisms with tunable dispersion for the THz frequency range,” J. Infrared Millim. Terahertz Waves 39, 553–560 (2018).
[Crossref]

Burnett, A. D.

N. Greenall, A. Valavanis, H. J. Desai, D. O. Acheampong, L. H. Li, J. E. Cunningham, A. G. Davies, E. H. Linfield, and A. D. Burnett, “The development of a Semtex-H simulant for terahertz spectroscopy,” J. Infrared Millim. Terahertz Waves 38, 325–338 (2017).
[Crossref]

Busch, S. F.

S. F. Busch, E. Castro-Camus, F. Beltran-Mejia, J. C. Balzer, and M. Koch, “3D printed prisms with tunable dispersion for the THz frequency range,” J. Infrared Millim. Terahertz Waves 39, 553–560 (2018).
[Crossref]

S. F. Busch, M. Weidenbach, J. C. Balzer, and M. Koch, “THz optics 3D printed with TOPAS,” J. Infrared Millim. Terahertz Waves 37, 303–307 (2016).
[Crossref]

S. F. Busch, M. Weidenbach, M. Fey, F. Schäfer, T. Probst, and M. Koch, “Optical properties of 3D printable plastics in the THz regime and their application for 3D printed THz optics,” J. Infrared Millim. Terahertz Waves 35, 993–997 (2014).
[Crossref]

But, D. B.

Cai, B.

B. Cai, H. Chen, G. Xu, H. Zhao, and O. Sugihara, “Ultra-broadband THz antireflective coating with polymer composites,” Polymers 9, 574 (2017).
[Crossref]

G. Xu, J. Zhang, X. Zang, O. Sugihara, H. Zhao, and B. Cai, “0.1–20 THz ultra-broadband perfect absorber via a flat multi-layer structure,” Opt. Express 24, 23177–23185 (2016).
[Crossref]

Castro-Camus, E.

S. F. Busch, E. Castro-Camus, F. Beltran-Mejia, J. C. Balzer, and M. Koch, “3D printed prisms with tunable dispersion for the THz frequency range,” J. Infrared Millim. Terahertz Waves 39, 553–560 (2018).
[Crossref]

A. I. Hernandez-Serrano and E. Castro-Camus, “Quasi-Wollaston-prism for terahertz frequencies fabricated by 3D printing,” J. Infrared Millim. Terahertz Waves 38, 567–573 (2017).
[Crossref]

Chen, H.

B. Cai, H. Chen, G. Xu, H. Zhao, and O. Sugihara, “Ultra-broadband THz antireflective coating with polymer composites,” Polymers 9, 574 (2017).
[Crossref]

Chen, P.

Colla, J. A.

J. A. Colla, R. E. M. Vickers, M. Nancarrow, and R. A. Lewis, “3D printing metallized plastics as terahertz reflectors,” J. Infrared Millim. Terahertz Waves 40, 752–762 (2019).
[Crossref]

Constable, E.

A. D. Squires, E. Constable, and R. A. Lewis, “3D printed terahertz diffraction grating and lenses,” J. Infrared Millim. Terahertz Waves 36, 72–80 (2015).
[Crossref]

Coquillat, D.

Cunningham, J. E.

N. Greenall, A. Valavanis, H. J. Desai, D. O. Acheampong, L. H. Li, J. E. Cunningham, A. G. Davies, E. H. Linfield, and A. D. Burnett, “The development of a Semtex-H simulant for terahertz spectroscopy,” J. Infrared Millim. Terahertz Waves 38, 325–338 (2017).
[Crossref]

Cywinski, G.

Davies, A. G.

N. Greenall, A. Valavanis, H. J. Desai, D. O. Acheampong, L. H. Li, J. E. Cunningham, A. G. Davies, E. H. Linfield, and A. D. Burnett, “The development of a Semtex-H simulant for terahertz spectroscopy,” J. Infrared Millim. Terahertz Waves 38, 325–338 (2017).
[Crossref]

Desai, H. J.

N. Greenall, A. Valavanis, H. J. Desai, D. O. Acheampong, L. H. Li, J. E. Cunningham, A. G. Davies, E. H. Linfield, and A. D. Burnett, “The development of a Semtex-H simulant for terahertz spectroscopy,” J. Infrared Millim. Terahertz Waves 38, 325–338 (2017).
[Crossref]

Feduniewicz-Zmuda, A.

Fey, M.

S. F. Busch, M. Weidenbach, M. Fey, F. Schäfer, T. Probst, and M. Koch, “Optical properties of 3D printable plastics in the THz regime and their application for 3D printed THz optics,” J. Infrared Millim. Terahertz Waves 35, 993–997 (2014).
[Crossref]

Fujita, K.

Gallot, G.

Ge, S.

Gehm, M. E.

Golish, D. R.

Gong, C.

Greenall, N.

N. Greenall, A. Valavanis, H. J. Desai, D. O. Acheampong, L. H. Li, J. E. Cunningham, A. G. Davies, E. H. Linfield, and A. D. Burnett, “The development of a Semtex-H simulant for terahertz spectroscopy,” J. Infrared Millim. Terahertz Waves 38, 325–338 (2017).
[Crossref]

Gui, X.

Heidemeyer, P.

Hernandez-Serrano, A. I.

A. I. Hernandez-Serrano and E. Castro-Camus, “Quasi-Wollaston-prism for terahertz frequencies fabricated by 3D printing,” J. Infrared Millim. Terahertz Waves 38, 567–573 (2017).
[Crossref]

Hiramatsu, M.

G. Takebe, Y. Kawada, K. Akiyama, H. Takahashi, H. Takamoto, and M. Hiramatsu, “Evaluation of drug crystallinity in aqueous suspension using terahertz time-domain attenuated total reflection spectroscopy,” J. Pharm. Sci. 102, 4065–4071 (2013).
[Crossref]

Hochrein, T.

Hong, Z.

Horita, K.

Hu, W.

Hwang, S.

Islam, S.

S. Islam, J. Stiens, G. Poesen, I. Jaeger, W. D. Raedt, and R. Vounckx, “Periodicity perturbed grounded frequency selective surface arrays as millimeter wave random phase coherence destroying diffusers,” J. Infrared Millim. Terahertz Waves 31, 641–648 (2010).
[Crossref]

Jaeger, I.

S. Islam, J. Stiens, G. Poesen, I. Jaeger, W. D. Raedt, and R. Vounckx, “Periodicity perturbed grounded frequency selective surface arrays as millimeter wave random phase coherence destroying diffusers,” J. Infrared Millim. Terahertz Waves 31, 641–648 (2010).
[Crossref]

Jang, J.-H.

Jing, X.

Kariz, M.

M. Kariz, M. Sernek, M. Obućina, and M. K. Kuzman, “Effect of wood content in FDM filament on properties of 3D printed parts,” Mater. Today Commun. 14, 135–140 (2018).
[Crossref]

Kawada, Y.

G. Takebe, Y. Kawada, K. Akiyama, H. Takahashi, H. Takamoto, and M. Hiramatsu, “Evaluation of drug crystallinity in aqueous suspension using terahertz time-domain attenuated total reflection spectroscopy,” J. Pharm. Sci. 102, 4065–4071 (2013).
[Crossref]

A. Nakanishi, Y. Kawada, T. Yasuda, K. Akiyama, and H. Takahashi, “Terahertz time domain attenuated total reflection spectroscopy with an integrated prism system,” Rev. Sci. Instrum. 83, 033103 (2012).
[Crossref]

Kelly, M.

A. D. Squires, M. Kelly, and R. A. Lewis, “Terahertz analysis of quinacridone pigments,” J. Infrared Millim. Terahertz Waves 38, 314–324 (2017).
[Crossref]

Kim, D.-H.

Kim, D.-S.

Knap, W.

Koch, M.

S. F. Busch, E. Castro-Camus, F. Beltran-Mejia, J. C. Balzer, and M. Koch, “3D printed prisms with tunable dispersion for the THz frequency range,” J. Infrared Millim. Terahertz Waves 39, 553–560 (2018).
[Crossref]

S. F. Busch, M. Weidenbach, J. C. Balzer, and M. Koch, “THz optics 3D printed with TOPAS,” J. Infrared Millim. Terahertz Waves 37, 303–307 (2016).
[Crossref]

S. F. Busch, M. Weidenbach, M. Fey, F. Schäfer, T. Probst, and M. Koch, “Optical properties of 3D printable plastics in the THz regime and their application for 3D printed THz optics,” J. Infrared Millim. Terahertz Waves 35, 993–997 (2014).
[Crossref]

M. Wichmann, A. S. Mondol, N. Kocic, S. Lippert, T. Probst, M. Schwerdtfeger, S. Schumann, T. Hochrein, P. Heidemeyer, M. Bastian, G. Bastian, and M. Koch, “Terahertz plastic compound lenses,” Appl. Opt. 52, 4186–4191 (2013).
[Crossref]

B. Scherger, S. Wietzke, M. Scheller, N. Vieweg, M. Wichmann, M. Koch, and K. Wiesauer, “Characterization of micro-powders for fabrication of compression molded THz lenses,” J. Infrared Millim. Terahertz Waves 32, 943–951 (2011).
[Crossref]

Kocic, N.

Kuzman, M. K.

M. Kariz, M. Sernek, M. Obućina, and M. K. Kuzman, “Effect of wood content in FDM filament on properties of 3D printed parts,” Mater. Today Commun. 14, 135–140 (2018).
[Crossref]

Leonhardt, R.

D. W. Vogt and R. Leonhardt, “3D-printed broadband dielectric tube terahertz waveguide with anti-reflection structure,” J. Infrared Millim. Terahertz Waves 37, 1086–1095 (2016).
[Crossref]

Lewis, R. A.

A. D. Squires and R. A. Lewis, “Terahertz analysis of phthalocyanine pigments,” J. Infrared Millim. Terahertz Waves 40, 738–751 (2019).
[Crossref]

J. A. Colla, R. E. M. Vickers, M. Nancarrow, and R. A. Lewis, “3D printing metallized plastics as terahertz reflectors,” J. Infrared Millim. Terahertz Waves 40, 752–762 (2019).
[Crossref]

A. D. Squires and R. A. Lewis, “Feasibility and characterization of common and exotic filaments for use in 3D printed terahertz device,” J. Infrared Millim. Terahertz Waves 39, 614–635 (2018).
[Crossref]

A. D. Squires, M. Kelly, and R. A. Lewis, “Terahertz analysis of quinacridone pigments,” J. Infrared Millim. Terahertz Waves 38, 314–324 (2017).
[Crossref]

A. D. Squires, E. Constable, and R. A. Lewis, “3D printed terahertz diffraction grating and lenses,” J. Infrared Millim. Terahertz Waves 36, 72–80 (2015).
[Crossref]

Li, L. H.

N. Greenall, A. Valavanis, H. J. Desai, D. O. Acheampong, L. H. Li, J. E. Cunningham, A. G. Davies, E. H. Linfield, and A. D. Burnett, “The development of a Semtex-H simulant for terahertz spectroscopy,” J. Infrared Millim. Terahertz Waves 38, 325–338 (2017).
[Crossref]

Lin, L.

Linfield, E. H.

N. Greenall, A. Valavanis, H. J. Desai, D. O. Acheampong, L. H. Li, J. E. Cunningham, A. G. Davies, E. H. Linfield, and A. D. Burnett, “The development of a Semtex-H simulant for terahertz spectroscopy,” J. Infrared Millim. Terahertz Waves 38, 325–338 (2017).
[Crossref]

Lippert, S.

Liu, W.

Lu, Y.

Mondol, A. S.

Nakajima, M.

Nakanishi, A.

Nancarrow, M.

J. A. Colla, R. E. M. Vickers, M. Nancarrow, and R. A. Lewis, “3D printing metallized plastics as terahertz reflectors,” J. Infrared Millim. Terahertz Waves 40, 752–762 (2019).
[Crossref]

Ng, W.-R.

Nowakowska-Siwinska, A.

Obucina, M.

M. Kariz, M. Sernek, M. Obućina, and M. K. Kuzman, “Effect of wood content in FDM filament on properties of 3D printed parts,” Mater. Today Commun. 14, 135–140 (2018).
[Crossref]

Okano, M.

M. Okano and S. Watanabe, “Internal status of visibly opaque black rubbers investigated by terahertz polarization spectroscopy: fundamentals and applications,” Polymers 11, 9 (2019).
[Crossref]

Pepper, M.

Y. C. Shen, P. F. Taday, and M. Pepper, “Elimination of scattering effects in spectral measurement of granulated materials using terahertz pulsed spectroscopy,” Appl. Phys. Lett. 92, 051103 (2008).
[Crossref]

Poesen, G.

S. Islam, J. Stiens, G. Poesen, I. Jaeger, W. D. Raedt, and R. Vounckx, “Periodicity perturbed grounded frequency selective surface arrays as millimeter wave random phase coherence destroying diffusers,” J. Infrared Millim. Terahertz Waves 31, 641–648 (2010).
[Crossref]

Probst, T.

S. F. Busch, M. Weidenbach, M. Fey, F. Schäfer, T. Probst, and M. Koch, “Optical properties of 3D printable plastics in the THz regime and their application for 3D printed THz optics,” J. Infrared Millim. Terahertz Waves 35, 993–997 (2014).
[Crossref]

M. Wichmann, A. S. Mondol, N. Kocic, S. Lippert, T. Probst, M. Schwerdtfeger, S. Schumann, T. Hochrein, P. Heidemeyer, M. Bastian, G. Bastian, and M. Koch, “Terahertz plastic compound lenses,” Appl. Opt. 52, 4186–4191 (2013).
[Crossref]

Rachon, M.

Raedt, W. D.

S. Islam, J. Stiens, G. Poesen, I. Jaeger, W. D. Raedt, and R. Vounckx, “Periodicity perturbed grounded frequency selective surface arrays as millimeter wave random phase coherence destroying diffusers,” J. Infrared Millim. Terahertz Waves 31, 641–648 (2010).
[Crossref]

Schäfer, F.

S. F. Busch, M. Weidenbach, M. Fey, F. Schäfer, T. Probst, and M. Koch, “Optical properties of 3D printable plastics in the THz regime and their application for 3D printed THz optics,” J. Infrared Millim. Terahertz Waves 35, 993–997 (2014).
[Crossref]

Scheller, M.

B. Scherger, S. Wietzke, M. Scheller, N. Vieweg, M. Wichmann, M. Koch, and K. Wiesauer, “Characterization of micro-powders for fabrication of compression molded THz lenses,” J. Infrared Millim. Terahertz Waves 32, 943–951 (2011).
[Crossref]

Scherger, B.

B. Scherger, S. Wietzke, M. Scheller, N. Vieweg, M. Wichmann, M. Koch, and K. Wiesauer, “Characterization of micro-powders for fabrication of compression molded THz lenses,” J. Infrared Millim. Terahertz Waves 32, 943–951 (2011).
[Crossref]

Schumann, S.

Schwerdtfeger, M.

Sernek, M.

M. Kariz, M. Sernek, M. Obućina, and M. K. Kuzman, “Effect of wood content in FDM filament on properties of 3D printed parts,” Mater. Today Commun. 14, 135–140 (2018).
[Crossref]

Shen, Y. C.

Y. C. Shen, P. F. Taday, and M. Pepper, “Elimination of scattering effects in spectral measurement of granulated materials using terahertz pulsed spectroscopy,” Appl. Phys. Lett. 92, 051103 (2008).
[Crossref]

Skierbiszewski, C.

Squires, A. D.

A. D. Squires and R. A. Lewis, “Terahertz analysis of phthalocyanine pigments,” J. Infrared Millim. Terahertz Waves 40, 738–751 (2019).
[Crossref]

A. D. Squires and R. A. Lewis, “Feasibility and characterization of common and exotic filaments for use in 3D printed terahertz device,” J. Infrared Millim. Terahertz Waves 39, 614–635 (2018).
[Crossref]

A. D. Squires, M. Kelly, and R. A. Lewis, “Terahertz analysis of quinacridone pigments,” J. Infrared Millim. Terahertz Waves 38, 314–324 (2017).
[Crossref]

A. D. Squires, E. Constable, and R. A. Lewis, “3D printed terahertz diffraction grating and lenses,” J. Infrared Millim. Terahertz Waves 36, 72–80 (2015).
[Crossref]

Stiens, J.

S. Islam, J. Stiens, G. Poesen, I. Jaeger, W. D. Raedt, and R. Vounckx, “Periodicity perturbed grounded frequency selective surface arrays as millimeter wave random phase coherence destroying diffusers,” J. Infrared Millim. Terahertz Waves 31, 641–648 (2010).
[Crossref]

Sugihara, O.

B. Cai, H. Chen, G. Xu, H. Zhao, and O. Sugihara, “Ultra-broadband THz antireflective coating with polymer composites,” Polymers 9, 574 (2017).
[Crossref]

G. Xu, J. Zhang, X. Zang, O. Sugihara, H. Zhao, and B. Cai, “0.1–20 THz ultra-broadband perfect absorber via a flat multi-layer structure,” Opt. Express 24, 23177–23185 (2016).
[Crossref]

Sun, L.

Suszek, J.

Sypek, M.

Szkudlarek, K.

Taday, P. F.

Y. C. Shen, P. F. Taday, and M. Pepper, “Elimination of scattering effects in spectral measurement of granulated materials using terahertz pulsed spectroscopy,” Appl. Phys. Lett. 92, 051103 (2008).
[Crossref]

Takahashi, H.

A. Nakanishi, K. Fujita, K. Horita, and H. Takahashi, “Terahertz imaging with room-temperature terahertz difference-frequency quantum-cascade laser sources,” Opt. Express 27, 1884–1893 (2019).
[Crossref]

A. Nakanishi and H. Takahashi, “Terahertz optical material based on wood-plastic composites,” Opt. Mater. Express 8, 3653–3658 (2018).
[Crossref]

G. Takebe, Y. Kawada, K. Akiyama, H. Takahashi, H. Takamoto, and M. Hiramatsu, “Evaluation of drug crystallinity in aqueous suspension using terahertz time-domain attenuated total reflection spectroscopy,” J. Pharm. Sci. 102, 4065–4071 (2013).
[Crossref]

A. Nakanishi, Y. Kawada, T. Yasuda, K. Akiyama, and H. Takahashi, “Terahertz time domain attenuated total reflection spectroscopy with an integrated prism system,” Rev. Sci. Instrum. 83, 033103 (2012).
[Crossref]

Takamoto, H.

G. Takebe, Y. Kawada, K. Akiyama, H. Takahashi, H. Takamoto, and M. Hiramatsu, “Evaluation of drug crystallinity in aqueous suspension using terahertz time-domain attenuated total reflection spectroscopy,” J. Pharm. Sci. 102, 4065–4071 (2013).
[Crossref]

Takebe, G.

G. Takebe, Y. Kawada, K. Akiyama, H. Takahashi, H. Takamoto, and M. Hiramatsu, “Evaluation of drug crystallinity in aqueous suspension using terahertz time-domain attenuated total reflection spectroscopy,” J. Pharm. Sci. 102, 4065–4071 (2013).
[Crossref]

Tian, H.

Tian, Y.

Tonouchi, M.

M. Tonouchi, “Cutting-edge terahertz technology,” Nat. Photonics 1, 97–105 (2007).
[Crossref]

Valavanis, A.

N. Greenall, A. Valavanis, H. J. Desai, D. O. Acheampong, L. H. Li, J. E. Cunningham, A. G. Davies, E. H. Linfield, and A. D. Burnett, “The development of a Semtex-H simulant for terahertz spectroscopy,” J. Infrared Millim. Terahertz Waves 38, 325–338 (2017).
[Crossref]

Vickers, R. E. M.

J. A. Colla, R. E. M. Vickers, M. Nancarrow, and R. A. Lewis, “3D printing metallized plastics as terahertz reflectors,” J. Infrared Millim. Terahertz Waves 40, 752–762 (2019).
[Crossref]

Vieweg, N.

B. Scherger, S. Wietzke, M. Scheller, N. Vieweg, M. Wichmann, M. Koch, and K. Wiesauer, “Characterization of micro-powders for fabrication of compression molded THz lenses,” J. Infrared Millim. Terahertz Waves 32, 943–951 (2011).
[Crossref]

Vogt, D. W.

D. W. Vogt and R. Leonhardt, “3D-printed broadband dielectric tube terahertz waveguide with anti-reflection structure,” J. Infrared Millim. Terahertz Waves 37, 1086–1095 (2016).
[Crossref]

Vounckx, R.

S. Islam, J. Stiens, G. Poesen, I. Jaeger, W. D. Raedt, and R. Vounckx, “Periodicity perturbed grounded frequency selective surface arrays as millimeter wave random phase coherence destroying diffusers,” J. Infrared Millim. Terahertz Waves 31, 641–648 (2010).
[Crossref]

Wang, L.

Watanabe, S.

M. Okano and S. Watanabe, “Internal status of visibly opaque black rubbers investigated by terahertz polarization spectroscopy: fundamentals and applications,” Polymers 11, 9 (2019).
[Crossref]

Wegrzynska, K.

Weidenbach, M.

S. F. Busch, M. Weidenbach, J. C. Balzer, and M. Koch, “THz optics 3D printed with TOPAS,” J. Infrared Millim. Terahertz Waves 37, 303–307 (2016).
[Crossref]

S. F. Busch, M. Weidenbach, M. Fey, F. Schäfer, T. Probst, and M. Koch, “Optical properties of 3D printable plastics in the THz regime and their application for 3D printed THz optics,” J. Infrared Millim. Terahertz Waves 35, 993–997 (2014).
[Crossref]

Wichmann, M.

M. Wichmann, A. S. Mondol, N. Kocic, S. Lippert, T. Probst, M. Schwerdtfeger, S. Schumann, T. Hochrein, P. Heidemeyer, M. Bastian, G. Bastian, and M. Koch, “Terahertz plastic compound lenses,” Appl. Opt. 52, 4186–4191 (2013).
[Crossref]

B. Scherger, S. Wietzke, M. Scheller, N. Vieweg, M. Wichmann, M. Koch, and K. Wiesauer, “Characterization of micro-powders for fabrication of compression molded THz lenses,” J. Infrared Millim. Terahertz Waves 32, 943–951 (2011).
[Crossref]

Wiesauer, K.

B. Scherger, S. Wietzke, M. Scheller, N. Vieweg, M. Wichmann, M. Koch, and K. Wiesauer, “Characterization of micro-powders for fabrication of compression molded THz lenses,” J. Infrared Millim. Terahertz Waves 32, 943–951 (2011).
[Crossref]

Wietzke, S.

B. Scherger, S. Wietzke, M. Scheller, N. Vieweg, M. Wichmann, M. Koch, and K. Wiesauer, “Characterization of micro-powders for fabrication of compression molded THz lenses,” J. Infrared Millim. Terahertz Waves 32, 943–951 (2011).
[Crossref]

Wojdyla, A.

Xia, R.

Xin, H.

Xu, G.

B. Cai, H. Chen, G. Xu, H. Zhao, and O. Sugihara, “Ultra-broadband THz antireflective coating with polymer composites,” Polymers 9, 574 (2017).
[Crossref]

G. Xu, J. Zhang, X. Zang, O. Sugihara, H. Zhao, and B. Cai, “0.1–20 THz ultra-broadband perfect absorber via a flat multi-layer structure,” Opt. Express 24, 23177–23185 (2016).
[Crossref]

Yahniuk, I.

Yang, J.

Yasuda, T.

A. Nakanishi, Y. Kawada, T. Yasuda, K. Akiyama, and H. Takahashi, “Terahertz time domain attenuated total reflection spectroscopy with an integrated prism system,” Rev. Sci. Instrum. 83, 033103 (2012).
[Crossref]

Yatsunenko, S.

Zagrajek, P.

Zang, X.

Zhang, J.

Zhao, H.

B. Cai, H. Chen, G. Xu, H. Zhao, and O. Sugihara, “Ultra-broadband THz antireflective coating with polymer composites,” Polymers 9, 574 (2017).
[Crossref]

G. Xu, J. Zhang, X. Zang, O. Sugihara, H. Zhao, and B. Cai, “0.1–20 THz ultra-broadband perfect absorber via a flat multi-layer structure,” Opt. Express 24, 23177–23185 (2016).
[Crossref]

Zhao, J.

Appl. Opt. (1)

Appl. Phys. Lett. (1)

Y. C. Shen, P. F. Taday, and M. Pepper, “Elimination of scattering effects in spectral measurement of granulated materials using terahertz pulsed spectroscopy,” Appl. Phys. Lett. 92, 051103 (2008).
[Crossref]

J. Infrared Millim. Terahertz Waves (13)

J. A. Colla, R. E. M. Vickers, M. Nancarrow, and R. A. Lewis, “3D printing metallized plastics as terahertz reflectors,” J. Infrared Millim. Terahertz Waves 40, 752–762 (2019).
[Crossref]

S. F. Busch, M. Weidenbach, M. Fey, F. Schäfer, T. Probst, and M. Koch, “Optical properties of 3D printable plastics in the THz regime and their application for 3D printed THz optics,” J. Infrared Millim. Terahertz Waves 35, 993–997 (2014).
[Crossref]

A. D. Squires and R. A. Lewis, “Feasibility and characterization of common and exotic filaments for use in 3D printed terahertz device,” J. Infrared Millim. Terahertz Waves 39, 614–635 (2018).
[Crossref]

S. F. Busch, M. Weidenbach, J. C. Balzer, and M. Koch, “THz optics 3D printed with TOPAS,” J. Infrared Millim. Terahertz Waves 37, 303–307 (2016).
[Crossref]

A. D. Squires, E. Constable, and R. A. Lewis, “3D printed terahertz diffraction grating and lenses,” J. Infrared Millim. Terahertz Waves 36, 72–80 (2015).
[Crossref]

D. W. Vogt and R. Leonhardt, “3D-printed broadband dielectric tube terahertz waveguide with anti-reflection structure,” J. Infrared Millim. Terahertz Waves 37, 1086–1095 (2016).
[Crossref]

S. F. Busch, E. Castro-Camus, F. Beltran-Mejia, J. C. Balzer, and M. Koch, “3D printed prisms with tunable dispersion for the THz frequency range,” J. Infrared Millim. Terahertz Waves 39, 553–560 (2018).
[Crossref]

A. I. Hernandez-Serrano and E. Castro-Camus, “Quasi-Wollaston-prism for terahertz frequencies fabricated by 3D printing,” J. Infrared Millim. Terahertz Waves 38, 567–573 (2017).
[Crossref]

B. Scherger, S. Wietzke, M. Scheller, N. Vieweg, M. Wichmann, M. Koch, and K. Wiesauer, “Characterization of micro-powders for fabrication of compression molded THz lenses,” J. Infrared Millim. Terahertz Waves 32, 943–951 (2011).
[Crossref]

S. Islam, J. Stiens, G. Poesen, I. Jaeger, W. D. Raedt, and R. Vounckx, “Periodicity perturbed grounded frequency selective surface arrays as millimeter wave random phase coherence destroying diffusers,” J. Infrared Millim. Terahertz Waves 31, 641–648 (2010).
[Crossref]

N. Greenall, A. Valavanis, H. J. Desai, D. O. Acheampong, L. H. Li, J. E. Cunningham, A. G. Davies, E. H. Linfield, and A. D. Burnett, “The development of a Semtex-H simulant for terahertz spectroscopy,” J. Infrared Millim. Terahertz Waves 38, 325–338 (2017).
[Crossref]

A. D. Squires, M. Kelly, and R. A. Lewis, “Terahertz analysis of quinacridone pigments,” J. Infrared Millim. Terahertz Waves 38, 314–324 (2017).
[Crossref]

A. D. Squires and R. A. Lewis, “Terahertz analysis of phthalocyanine pigments,” J. Infrared Millim. Terahertz Waves 40, 738–751 (2019).
[Crossref]

J. Pharm. Sci. (1)

G. Takebe, Y. Kawada, K. Akiyama, H. Takahashi, H. Takamoto, and M. Hiramatsu, “Evaluation of drug crystallinity in aqueous suspension using terahertz time-domain attenuated total reflection spectroscopy,” J. Pharm. Sci. 102, 4065–4071 (2013).
[Crossref]

Mater. Today Commun. (1)

M. Kariz, M. Sernek, M. Obućina, and M. K. Kuzman, “Effect of wood content in FDM filament on properties of 3D printed parts,” Mater. Today Commun. 14, 135–140 (2018).
[Crossref]

Nat. Photonics (1)

M. Tonouchi, “Cutting-edge terahertz technology,” Nat. Photonics 1, 97–105 (2007).
[Crossref]

Opt. Express (7)

A. Nakanishi, K. Fujita, K. Horita, and H. Takahashi, “Terahertz imaging with room-temperature terahertz difference-frequency quantum-cascade laser sources,” Opt. Express 27, 1884–1893 (2019).
[Crossref]

A. Wojdyla and G. Gallot, “Brewster’s angle silicon wafer terahertz linear polarizer,” Opt. Express 19, 14099–14107 (2011).
[Crossref]

W.-R. Ng, D. R. Golish, H. Xin, and M. E. Gehm, “Direct rapid-prototyping fabrication of computer-generated volume holograms in the millimeter-wave and terahertz regime,” Opt. Express 22, 3349–3355 (2014).
[Crossref]

G. Xu, J. Zhang, X. Zang, O. Sugihara, H. Zhao, and B. Cai, “0.1–20 THz ultra-broadband perfect absorber via a flat multi-layer structure,” Opt. Express 24, 23177–23185 (2016).
[Crossref]

D.-S. Kim, D.-H. Kim, S. Hwang, and J.-H. Jang, “Broadband terahertz absorber realized by self-assembled multilayer glass spheres,” Opt. Express 20, 13566–13572 (2012).
[Crossref]

K. Szkudlarek, M. Sypek, G. Cywiński, J. Suszek, P. Zagrajek, A. Feduniewicz-Żmuda, I. Yahniuk, S. Yatsunenko, A. Nowakowska-Siwińska, D. Coquillat, D. B. But, M. Rachoń, K. Węgrzyńska, C. Skierbiszewski, and W. Knap, “Terahertz 3D printed diffractive lens matrices for field-effect transistor detector focal plane arrays,” Opt. Express 24, 20119–20131 (2016).
[Crossref]

J. Yang, J. Zhao, C. Gong, H. Tian, L. Sun, P. Chen, L. Lin, and W. Liu, “3D printed low-loss THz waveguide based on Kagome photonic crystal structure,” Opt. Express 24, 22454–22460 (2016).
[Crossref]

Opt. Mater. Express (3)

Polymers (2)

B. Cai, H. Chen, G. Xu, H. Zhao, and O. Sugihara, “Ultra-broadband THz antireflective coating with polymer composites,” Polymers 9, 574 (2017).
[Crossref]

M. Okano and S. Watanabe, “Internal status of visibly opaque black rubbers investigated by terahertz polarization spectroscopy: fundamentals and applications,” Polymers 11, 9 (2019).
[Crossref]

Rev. Sci. Instrum. (1)

A. Nakanishi, Y. Kawada, T. Yasuda, K. Akiyama, and H. Takahashi, “Terahertz time domain attenuated total reflection spectroscopy with an integrated prism system,” Rev. Sci. Instrum. 83, 033103 (2012).
[Crossref]

Cited By

OSA participates in Crossref's Cited-By Linking service. Citing articles from OSA journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (7)

Fig. 1.
Fig. 1. Photographs of WPC samples. (a) WPC made of PS and (b) WPC made of PP.
Fig. 2.
Fig. 2. Schematic representation of the transmission measurement of WPC samples. (a) Vertical polarization; (b) horizontal polarization.
Fig. 3.
Fig. 3. Optical properties of several WPCs having different wood powder contents (PP). (a) Refractive index and (b) absorption coefficient.
Fig. 4.
Fig. 4. Optical properties of several WPCs having different wood powder contents (PS). (a) Refractive index and (b) absorption coefficient.
Fig. 5.
Fig. 5. Photograph of wood powder obtained by laser scanning microscopy.
Fig. 6.
Fig. 6. Optical properties of several WPCs having different wood powder contents (PP) with vertical polarization (see above) and horizontal polarization: (a) refractive index, and (b) absorption coefficient.
Fig. 7.
Fig. 7. Optical properties of several WPCs having different wood powder contents (PS) with vertical polarization (see above) and horizontal polarization: (a) refractive index, and (b) absorption coefficient.

Tables (2)

Tables Icon

Table 1. Water Contents of Samples Having Different Wood Powder Contents (PS)

Tables Icon

Table 2. Water Contents of Samples Having Different Wood Powder Contents (PP)

Metrics