Open Access
Add to BibSonomy
Abstract
The insufficient photosensitivity of conventional organic recording materials such as phenanthraquinone-doped poly(methyl methacrylate) (PQ/PMMA) significantly limits the recording speed in holographic data storage. Accelerating the formation of free radicals using the photosensitizer PQ during the photoreaction process and increasing the C = C double bond concentration of the matrix are effective methods for improving the photosensitivity. Using the above methods, we doped PQ/PMMA with the co-photoinitiator triethanolamine and co-monomer acrylamide to improve the photosensitivity of the material. Compared with the original PQ/PMMA material, the photosensitivity was increased by 10 times, and the diffraction efficiency was increased by 20%. The role of each doping component was studied by characterization and analysis. In addition, the introduction of the cross-linking agent N,N'-methylene-bisacrylamide, having high sensitivity, reduced the shrinkage of the material. We verified the application of the new material in a collinear system, and its high sensitivity showed its great potential for holographic data storage.
© 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement
1. Introduction
Multidimensional modulated optical data storage technologies [1,2] utilize various photophysical characteristics, including polarization [3], wavelength [4], intensity, and florescence [5] of various materials, or a combination of multiplexing technology [6]. The materials used include quartz glass [7], natural silk [8] and gold or silver nanoparticles [9,10]. These technologies provide novel and reliable approaches to optical data storage. Volume holographic data storage [11,12], utilizing multiple laser beams to record 2D information pages in a 3D photopolymer, is recognized as a promising optical data storage strategy owing to its high storage density, fast write/read speed, and economic sustainability [13]. Photopolymers have been extensively used for holographic data storage [14–16] because of their high resolution, real-time recording ability, and low cost [17–19], but the sensitivity and diffraction efficiency of photopolymers still have some room for improvement [20–22].
The photopolymer phenanthraquinone-doped poly(methyl methacrylate) (PQ/PMMA) is considered a promising holographic recording medium [23–25] because of its long-term stability, negligible volume shrinkage, and controllable thickness. In addition, PQ/PMMA has polarization properties [26], and polarization holography is regarded as a good candidate to replace the existing micro–nano technology [27] and manufacturing methods for light field control elements [28,29] and metamaterials [30]. However, the ever-increasing demand for data storage and reading speeds require materials with higher photosensitivity [6,31,32]. Various strategies have been proposed to enhance the holographic properties (e.g., introducing co-monomers [33–35], doping nanoparticles [36–38] and organometallic components [39,40] into methyl methacrylate (MMA) monomers), but have yielded little success. In the traditional PQ/PMMA system, the photosensitizer PQ slowly produces free radicals under excitation by light. Because the photosensitizer PQ becomes an electron acceptor under excitation by light, the addition of an electron acceptor co-photoinitiator accelerates the transfer rate between electrons, further accelerates the generation of free radicals from the excited PQ*, thereby the generation speed of photoproducts is increased, and thus the photosensitivity is improved. Simultaneously, the radicals mainly react with the C = C double bonds to generate photoproducts. Therefore, increasing the concentration of C = C double bonds is considered an effective way to improve the photoreaction speed of the material [41,42]. Hence, we chose the electron donor photoinitiator triethanolamine (TEA) and the co-monomer acrylamide (AA) with a C = C bond to improve the photosensitivity of the material. TEA can significantly accelerate the electron transfer process because of its electron donor characteristic [43–45], and it usually acts as an electron donor component in organic photovoltaics [46] and photocatalytic systems [47–49]. More importantly, combining TEA with an electron acceptor photosensitizer as an ideal co-photoinitiator can increase the photosensitivity of a photopolymer [50,51]. Therefore, TEA acts as an electron donor to form a new photoinitiated system with PQ, which can quickly provide electrons to the excited PQ*, thereby accelerating the generation of the photoproduct and significantly improving the photosensitivity. The co-monomer AA was selected to increase the vinyl concentration of the PQ/PMMA matrix, which provides the C = C bond directly to PQ* during the photoreaction, further enhancing the photopolymerization process. In addition, AA has been proven to initiate free-radical photopolymerization [52,53]. Meanwhile, material properties such as the mechanical hardness and volume shrinkage are enhanced by introducing macromolecules into the photopolymer matrix [54]. Thus, the cross-linking agent N,N'-methylene-bisacrylamide (MBA) can be used to increase both the molecular weight and structural strength of PQ/PMMA. MBA was cross-linked with the PMMA chain, and a macromolecular three-dimensional network structure was prepared in the thermal polymerization stage, which increased the mechanical properties and reduced the photo-induced volume shrinkage. The cross-linking effect of MBA has been verified in composite materials [55–57].
Herein, by introducing the co-photoinitiator TEA, co-monomer AA, and cross-linking agent MBA, a novel composite photopolymer, TEA/AA/PQ/MBA-PMMA (TAPMP), was prepared. We demonstrated that this novel composite exhibited high photosensitivity. The holographic photosensitivity of TAPMP was 10 times greater (from ∼0.27 cm/J to ∼3.0 cm/J) than that of the PQ/PMMA. The diffraction efficiency was enhanced by ∼20% (from ∼45% to ∼65%), and the photo-induced volume shrinkage was decreased by ∼50% (from ∼0.4% to ∼0.2%). The enhancement in the holographic properties and low-volume shrinkage allowed rapid recording on a collinear holographic data storage system to be achieved. Therefore, we successfully synthesized a novel composite photopolymer (TAPMP) with high photosensitivity, making it a promising candidate medium for holographic storage applications. The high photosensitivity exhibited by this new photoinitiated system composed of TEA and PQ provides extensive adaptability for subsequent research on thick-volume PQ/PMMA photopolymers.
2. Material preparation
The photopolymer material consisted of MMA and AA as monomers, MBA as the cross-linking agent, PQ as the photosensitizer, and TEA as the co-photoinitiator. In this study, the photopolymer preparation process and parameters were improved based on previous studies [20,24]. To obtain the novel composite photopolymer TAPMP, a two-stage polymerization process was performed, as shown in Fig. 1. The MMA was initially added to a 30 mL transparent glass bottle. Because of the limited solubility of MBA, its concentration was set at 0.5 wt% (relative to the MMA). To systemically evaluate the impact of TEA and AA molecules on the holographic properties of the PQ/PMMA photopolymer, different concentrations of AA and TEA were used (0.5, 1.0, 1.5, and 2.0 wt% relative to the MMA). The PQ photosensitizer (1.0 wt%) and AIBN (2,2-azo-bis-isobutyronitrile) thermo-initiator (1.0 wt%) were then added, where their proportions in the mixture were maintained at MMA: AIBN: PQ = 100:1:1. All the components were ultrasonically shaken in a water bath at 333 K for 30 min to form a homogeneous multi-component solution. During stirring pre-polymerization, the glass bottle was placed on a magnetic stirrer and kept at a constant temperature (333 K) for 80 min to make each solution homogeneously viscid. The viscous solutions were then poured into glass molds with 1.5 mm-thick spacers and placed horizontally in an oven at 333 K for 21 h until complete solidification.
3. Results and discussion
3.1 Holographic properties
First, the light absorption spectra of the TAPMP and PQ/PMMA samples were characterized using a UV-vis spectrophotometer. Plots of absorbance versus wavelength of the TAPMP and PQ/PMMA samples are shown in Fig. 2. We selected a green laser with a low optical absorption coefficient near 532 nm as the pump light source to avoid excessive optical absorption.
The experimental optical setup used for the diffraction efficiency measurement is shown in Fig. 3. The intensities of the signal and reference beams were set at 0.127 Wcm-2.
Fig. 3. Experimental setup for diffraction efficiency measurement (HWP: half-wave plate; PBS: polarization beam splitter; PD: photo detector; M: mirror).
During the holographic grating recording stage, the volume-holographic grating was recorded for 6 s, and the interference angle was set at 24°. In the reconstruction stage, the original reference waves were exploited to retrieve the grating for 0.4 s to obtain the corresponding diffracted light. The diffraction efficiency η is expressed as follows:
where I0 and I + 1 represent the intensities of the transmitting and first-order grating diffraction beams, respectively. Here, the signal and reference laser beams were set to s-pol, and the introduction of TEA and AA was set to be 1.0 wt%, which could effectively enhance the diffraction efficiency by more than 20% (the diffraction efficiency of the TAPMP photopolymer could reach up to ∼65%), as demonstrated in the curve in Fig. 4.The photosensitivity factor, S, of a material is calculated as follows [58,59]:
where I is the intensity of the recording wave (0.127 Wcm−2), d is the thickness of the material (1.5 mm), and η is the diffraction efficiency. As shown in Fig. 5, the photosensitivity of TAPMP was 10 times higher than that of PQ/PMMA (an increase from ∼0.27 cm/J to ∼3 cm/J).Meanwhile, response time [36] τ can be calculated as follows:
where ηsat denotes the saturation diffraction efficiency. As shown in Fig. 6, because of the enhanced photosensitivity, the response time (calculated using Eq. (3)) reduced significantly from ∼70.2 s to ∼4.2 s.It should be noted that, as shown in Fig. 7(a), the inclusion of TEA (1.0 wt%) could considerably enhance the photosensitivity (where the concentration of AA is 1.0 wt%); however, this enhancement tended to decrease with an increase in the TEA doping concentration. In addition, the diffraction efficiency of the AA-doped PQ/PMMA samples increased rapidly with an increase in the AA concentration but decreased when the concentration reached 2.0 wt% (where the concentration of TEA is 1.0 wt%), as seen in Fig. 7(b).
Fig. 7. Time-dependent intensity holographic diffraction efficiency values for PQ/PMMA and TAPMP materials with different (a) TEA (AA: 1 wt%) and (b) AA (TEA: 1 wt%) concentrations.
3.2 Reaction mechanism
Fourier transform infrared (FT-IR) spectroscopy was used to analyze the reason behind the improvement in the photosensitivity of the materials. It was also used to examine the role of TEA in the reaction as a photoinitiator and to monitor the change in the C = C double bond in the materials. FT-IR spectroscopy was performed on an IRAffinity-1S spectrometer using KBr pellets in the range of 4000–400 cm−1 with a resolution of 0.01 cm−1 to analyze the reaction mechanism of the TAPMP photopolymer during thermo- and photo-polymerization. AA and MBA were initially co-dissolved in methanol with MMA and AIBN, respectively, and the prepared solutions were stirred using a magnetic stirrer at 338 K for 24 h and then dried to obtain the corresponding precipitates of the characterized samples. In addition, by co-dissolving TEA, AA, and PQ uniformly in methanol, we obtained characterization samples with and without sunlight exposure for 10 h. Finally, purified AA&PMMA, AA&MBA&PMMA, TEA&PQ, and AA&PQ samples for FT-IR measurements were prepared.
The FT-IR spectroscopy results, illustrated in Fig. 8(a), clearly demonstrated that AA did not react with the PMMA chain during thermal polymerization. Compared with pristine PMMA, the characteristic transmission spectra of the AA + PMMA polymers did not exhibit new peaks and did not shift. In particular, in the spectrum of AA + PMMA, the two characteristic peaks of AA at high wavenumbers (N-H stretching vibrations at 3206 cm-1 and 3362 cm-1) and C = C stretching vibrations at 1612 cm−1 were clearly observed and did not shift compared to the spectrum of AA. Similarly, a comparison with the FT-IR spectra of AA + MBA-PMMA, as seen in Fig. 8(b), showed that there was no new chemical bond generation and bond shift, which revealed that the introduced AA did not react with the PMMA and MBA, thus providing a basis for the subsequent photoreaction of AA as a co-monomer with PQ. We also explored if the introduction of TEA would directly affect PQ. As shown in Fig. 8(c), the C = O (1665 cm−1) double bond and C-H (2949 cm−1) bond of TEA did not change before and after exposure, and there was no new bond generation or bond shift, which indicated that TEA as a co-photoinitiator did not directly react with PQ to generate photoproducts. Furthermore, the FT-IR spectra of AA + PQ before and after exposure, as shown in Fig. 8(d), indicated that PQ could react with the C = C bond of AA. In detail, C = C (1610 cm−1) was reduced after AA + PQ exposure, and two new absorption peaks (C-O-C bonds) were observed at 1182 cm−1 and 1319 cm−1, which stemmed from the photoinduced reaction between the quinone carbonyl group (C = O bond) in PQ and the vinyl group (C = C bond) in AA. As an electron donor photoinitiator, TEA only provided free electrons for excited PQ* in the free radical generation stage, which improved the generation rate of free radicals. This was the key to improving the photosensitivity of the materials. In addition, the FT-IR results clearly showed that the introduction of the co-monomer AA increased the concentration of the C = C double bonds in the material, which was conducive to the reaction with PQ to produce photoproducts in the photoreaction stage, thus improving the photosensitivity of the material.
Fig. 8. FT-IR spectra of (a) AA, PMMA, and AA + PMMA (AA: 1 wt%) (b) AA + MBA-PMMA (AA: 1 wt%, MBA: 1 wt%), MBA-PMMA (MBA: 1 wt%), and AA (c) TEA + PQ mixture before and after exposure (d) AA + PQ.
4. Collinear holographic storage system
We adopted a collinear holographic storage system to evaluate the high sensitivity and holographic storage performance of the TAPMP material [12]; a schematic diagram of which is shown in Fig. 9. The material was set up as a 50 mm × 50 mm × 0.5 mm yellow slice with mirrors.
The bit error rate (BER) and signal-to-noise ratio (SNR) were used to examine the quality of the reproduced images. The recording time-dependent BER (Fig. 10(a)) and SNR (Fig. 10(b)) curves showed that the TAPMP material could achieve holographic storage images with a shorter recording time, compared to the original PQ/PMMA material. The time to reach the same BER could be shortened from 40 s to 2 s. In detail, the BER decreased by approximately 20 times (from 89.1% to 4.2%), and the SNR increased by approximately 175% (from 1.20 to 3.31) in a recording time of 2 s. The image reconstructed using a collinear beam (∼0.438 mW with a beam diameter of ∼300 µm) with the TAPMP material (Fig. 10(c)), exhibited a lower BER and reliable SNR compared to the original PQ/PMMA material (Fig. 10(d)). The experimental results indicated that the TAPMP photopolymer could meet the demands of short-term recording in collinear holographic storage.
Fig. 10. (a) Recording time dependent BER and (b) SNR results of TAPMP and PQ/PMMA materials with collinear holographic storage system. Reconstructed images using (c) TAPMP and (d) PQ/PMMA after 2 s of exposure to collinear beam.
The volumetric shrinkage of the photopolymer is a crucial factor in holographic data storage as it causes significant grating distortion and Bragg shift, leading to data reading failure [60]. In general, high photosensitive photopolymers are accompanied by high photoinduced shrinkage. However, because of the addition of the cross-linking agent (MBA) in TAPMP, it not only had excellent holographic properties with high sensitivity but also had low photoinduced volumetric shrinkage. The experimental optical setup used for photoinduced volume shrinkage measurements is shown in Fig. 11.
The volume shrinkage, σ, of TAPMP during photopolymerization can be calculated as follows [61]:
where θtheo and θexp represent the theoretical and experimental values of the grating inclination angle, respectively. Here, the in situ volume shrinkage was characterized after rotating the sample by 10° from the two writing beams. As shown in Fig. 12, TAPMP exhibited a slight peak shift (∼0.02°), which was less than that of the PQ/PMMA photopolymer (∼0.04°). The volume shrinkages of TAPMP and PQ/PMMA calculated using Eq. (4) were 0.2% and 0.4%, respectively, further verifying the low volumetric shrinkage of the TAPMP photopolymer. The results proved that TAPMP overcame the large volume shrinkage problem of high-sensitivity holographic recording materials and showed great potential in holographic data storage.Fig. 12. Normalized diffraction efficiencies of 0.5 mm thick TAPMP and PQ/PMMA samples rotated 10° from the bisector of two incidence beams as a function of sample rotation angle.
5. Conclusion
In this study, we demonstrate that the photosensitivity of the TAPMP photopolymer can be significantly enhanced by introducing TEA and AA to PQ/PMMA. Specifically, as a co-photoinitiator, TEA can be used to form a new photoinitiator system with the photosensitizer PQ. Based on the new photoinitiator system, the introduction of the co-monomer AA and cross-linking agent MBA can improve the holographic properties of the material. Compared to the original PQ/PMMA, the holographic performance of TAPMP is significantly enhanced. The photosensitivity (∼3.0 cm/J) is enhanced by more than 10 times, the diffraction efficiency (∼65%) is increased by more than 20%, and the photo-induced volume shrinkage (∼0.2%) is decreased by approximately 50%. Ultrafast holographic storage recording on a collinear system is realized owing to the significantly enhanced holographic performance of the composite. This novel photoinitiated TAPMP system can provide a new strategy for fast holographic data storage with high photosensitivity.
Funding
National Key Research and Development Program of China (2018YFA0701800); Project of Fujian Province Major Science and Technology (2020HZ01012).
Disclosures
The authors declare no conflicts of interest.
Data availability
Data underlying the results presented in this paper are not publicly available at this time but may be obtained from the authors upon reasonable request.
References
1. M. Gu, X. Li, and Y. Cao, “Optical storage arrays: a perspective for future big data storage,” Light: Sci. Appl. 3(5), e177 (2014). [CrossRef]
2. E. N. Leith, A. Kozma, J. Upatnieks, J. Marks, and N. Massey, “Holographic Data Storage in Three-Dimensional Media,” Appl. Opt. 5(8), 1303–1311 (1966). [CrossRef]
3. C. Li, L. Cao, Z. Wang, and G. Jin, “Hybrid polarization-angle multiplexing for volume holography in gold nanoparticle-doped photopolymer,” Opt. Lett. 39(24), 6891–6894 (2014). [CrossRef]
4. S. Wu, S. Duan, Z. Lei, W. Su, Z. Zhang, K. Wang, and Q. Zhang, “Supramolecular bisazopolymers exhibiting enhanced photoinduced birefringence and enhanced stability of birefringence for four-dimensional optical recording,” J. Mater. Chem. 20(25), 5202–5209 (2010). [CrossRef]
5. L. Dhar, M. G. Schnoes, T. L. Wysocki, H. Bair, M. Schilling, and C. Boyd, “Temperature-induced changes in photopolymer volume holograms,” Appl. Phys. Lett. 73(10), 1337–1339 (1998). [CrossRef]
6. J. Zang, F. Fan, Y. Liu, R. Wei, and X. Tan, “Four-channel volume holographic recording with linear polarization holography,” Opt. Lett. 44(17), 4107–4110 (2019). [CrossRef]
7. J. Zhang, M. Gecevicius, M. Beresna, and P. G. Kazansky, “Seemingly unlimited lifetime data storage in nanostructured glass,” Phys. Rev. Lett. 112(3), 033901 (2014). [CrossRef]
8. W. Lee, Z. Zhou, X. Chen, N. Qin, J. Jiang, K. Liu, M. Liu, T. H. Tao, and W. Li, “A rewritable optical storage medium of silk proteins using near-field nano-optics,” Nat. Nanotechnol. 15(11), 941–947 (2020). [CrossRef]
9. P. Zijlstra, J. W. Chon, and M. Gu, “Five-dimensional optical recording mediated by surface plasmons in gold nanorods,” Nature 459(7245), 410–413 (2009). [CrossRef]
10. A. Royon, K. Bourhis, M. Bellec, G. Papon, B. Bousquet, Y. Deshayes, T. Cardinal, and L. Canioni, “Silver clusters embedded in glass as a perennial high capacity optical recording medium,” Adv. Mater. 22(46), 5282–5286 (2010). [CrossRef]
11. X. Lin, J. Liu, J. Hao, K. Wang, Y. Zhang, H. Li, H. Horimai, and X. Tan, “Collinear holographic data storage technologies,” Opto-Electron. Adv. 3(3), 190004 (2020). [CrossRef]
12. H. Horimai, X. Tan, and J. Li, “Collinear holography,” Appl. Opt. 44(13), 2575–2579 (2005). [CrossRef]
13. J. F. Heanue, M. C. Bashaw, and L. Hesselink, “Volume holographic storage and retrieval of digital data,” Science 265(5173), 749–752 (1994). [CrossRef]
14. M. Campbell, D. Sharp, M. Harrison, R. Denning, and A. Turberfield, “Fabrication of photonic crystals for the visible spectrum by holographic lithography,” Nature 404(6773), 53–56 (2000). [CrossRef]
15. S. Mavila, J. Sinha, Y. Hu, M. Podgorski, P. K. Shah, and C. N. Bowman, “High Refractive Index Photopolymers by Thiol-Yne “Click” Polymerization,” ACS Appl. Mater. Interfaces 13(13), 15647–15658 (2021). [CrossRef]
16. N. Suzuki and Y. Tomita, “Silica-nanoparticle-dispersed methacrylate photopolymers with net diffraction efficiency near 100%,” Appl. Opt. 43(10), 2125–2129 (2004). [CrossRef]
17. L. Carretero, A. Murciano, S. Blaya, M. Ulibarrena, and A. Fimia, “Acrylamide-N,N’-methylenebisacrylamide silica glass holographic recording material,” Opt. Express 12(8), 1780–1787 (2004). [CrossRef]
18. M. Květoň, V. Lédl, A. Havránek, and P. Fiala, “Photopolymer for Optical Holography and Holographic Interferometry,” Macromol. Symp. 295(1), 107–113 (2010). [CrossRef]
19. T. Mikulchyk, S. Martin, and I. Naydenova, “N-isopropylacrylamide-based photopolymer for holographic recording of thermosensitive transmission and reflection gratings,” Appl. Opt. 56(22), 6348–6356 (2017). [CrossRef]
20. P. Hu, Y. Chen, J. Li, J. Wang, J. Liu, T. Wu, and X. Tan, “Impact of fullerene on the holographic properties of PQ/PMMA photopolymer,” Compos. Sci. Technol. 221, 109335 (2022). [CrossRef]
21. H. Wang, J. Wang, H. Liu, D. Yu, X. Sun, and J. Zhang, “Study of effective optical thickness in photopolymer for application,” Opt. Lett. 37(12), 2241–2243 (2012). [CrossRef]
22. Y. Chen, P. Hu, Z. Huang, J. Wang, H. Song, X. Chen, X. Lin, T. Wu, and X. Tan, “Significant Enhancement of the Polarization Holographic Performance of Photopolymeric Materials by Introducing Graphene Oxide,” ACS Appl. Mater. Interfaces 13(23), 27500–27512 (2021). [CrossRef]
23. P. Liu, F. Chang, Y. Zhao, Z. Li, and X. Sun, “Ultrafast volume holographic storage on PQ/PMMA photopolymers with nanosecond pulsed exposures,” Opt. Express 26(2), 1072–1082 (2018). [CrossRef]
24. S. H. Lin, K. Y. Hsu, W.-Z. Chen, and W. T. Whang, “Phenanthrenequinone-doped poly(methyl methacrylate) photopolymer bulk for volume holographic data storage,” Opt. Lett. 25(7), 451–453 (2000). [CrossRef]
25. X. Sun, F. Chang, and K. Gai, “Optoelectronic Fast Response Properties of PQ/PMMA Polymer,” Mater. Today: Proc. 3(2), 632–634 (2016). [CrossRef]
26. J. Wang, X. Tan, P. Qi, C. Wu, L. Huang, X. Xu, Z. Huang, L. Zhu, Y. Zhang, X. Lin, J. Zang, and K. Kuroda, “Linear polarization holography,” Opto-Electron. Sci. 1(2), 210009 (2022). [CrossRef]
27. Y. Zhang, H. Liu, H. Cheng, J. Tian, and S. Chen, “Multidimensional manipulation of wave fields based on artificial microstructures,” Opto-Electron. Adv. 3(11), 200002 (2020). [CrossRef]
28. L. Huang, Y. Zhang, Q. Zhang, Y. Chen, X. Chen, Z. Huang, X. Lin, and X. Tan, “Generation of a vector light field based on polarization holography,” Opt. Lett. 46(18), 4542–4545 (2021). [CrossRef]
29. S. Zheng, H. Liu, A. Lin, X. Xu, S. Ke, H. Song, Y. Zhang, Z. Huang, and X. Tan, “Scalar vortex beam produced through faithful reconstruction of polarization holography,” Opt. Express 29(26), 43193–43202 (2021). [CrossRef]
30. L. Y. Beliaev, O. Takayama, P. N. Melentiev, and A. V. Lavrinenko, “Photoluminescence control by hyperbolic metamaterials and metasurfaces: a review,” Opto-Electron. Adv. 4(8), 210031 (2021). [CrossRef]
31. Y. Liu, Z. Li, J. Zang, A. A. Wu, J. Wang, X. Lin, X. Tan, D. Barada, T. Shimura, and K. Kuroda, “The optical polarization properties of phenanthrenequinone-doped Poly(methyl methacrylate) photopolymer materials for volume holographic storage,” Opt. Rev. 22(5), 837–840 (2015). [CrossRef]
32. Z. Huang, Y. Chen, H. Song, and X. Tan, “Faithful reconstruction in polarization holography suitable for high-speed recording and reconstructing,” Opt. Lett. 45(22), 6282–6285 (2020). [CrossRef]
33. L. P. Krul, V. Matusevich, D. Hoff, R. Kowarschik, Y. I. Matusevich, G. V. Butovskaya, and E. A. Murashko, “Modified polymethylmethacrylate as a base for thermostable optical recording media,” Opt. Express 15(14), 8543–8549 (2007). [CrossRef]
34. W. S. Kim, H.-S. Chang, Y.-C. Jeong, Y.-M. Lee, J.-K. Park, C.-W. Shin, K. Nam, and H.-J. Tak, “A new phase-stable photopolymer with high diffraction efficiency based on modified PMMA,” Opt. Commun. 249(1-3), 65–71 (2005). [CrossRef]
35. F. Fan, Y. Liu, Y. Hong, J. Zang, A. Wu, T. Zhao, G. Kang, X. Tan, and T. Shimura, “Improving the polarization-holography performance of PQ/PMMA photopolymer by doping with THMFA,” Opt. Express 26(14), 17794–17803 (2018). [CrossRef]
36. P. Liu, Y. Zhao, Z. Li, and X. Sun, “Improvement of ultrafast holographic performance in silver nanoprisms dispersed photopolymer,” Opt. Express 26(6), 6993–7004 (2018). [CrossRef]
37. Y. Liu, F. Fan, and X. Tan, “SiO2 NPs-PQ/PMMA Photopolymer Material Doped with a High-Concentration Photosensitizer for Holographic Storage,” Polymers 12(4), 816 (2020). [CrossRef]
38. Y. Tomita, E. Hata, K. Momose, S. Takayama, X. Liu, K. Chikama, J. Klepp, C. Pruner, and M. Fally, “Photopolymerizable nanocomposite photonic materials and their holographic applications in light and neutron optics,” J. Mod. Opt. 63(sup3), S1–S31 (2016). [CrossRef]
39. D. Yu, H. Liu, J. Wang, Y. Jiang, and X. Sun, “Study on holographic characteristics in ZnMA doped PQ-PMMA photopolymer,” Opt. Commun. 284(12), 2784–2788 (2011). [CrossRef]
40. Y.-N. Hsiao, W.-T. Whang, and S. H. Lin, “Effect of ZnMA on Optical and Holographic Characteristics of Doped PQ/PMMA Photopolymer,” Jpn. J. Appl. Phys. 44(2), 914–919 (2005). [CrossRef]
41. P.-L. Chen, “Phenanthrenequinone-doped copolymers for holographic data storage,” Opt. Eng. 48(3), 035802 (2009). [CrossRef]
42. G. J. Steckman, V. Shelkovnikov, V. Berezhnaya, T. Gerasimova, I. Solomatine, and D. Psaltis, “Holographic recording in a photopolymer by optically induced detachment of chromophores,” Opt. Lett. 25(9), 607–609 (2000). [CrossRef]
43. A. Gallastegui, A. Dominguez-Alfaro, L. Lezama, N. Alegret, M. Prato, M. L. Gómez, and D. Mecerreyes, “Fast Visible-Light Photopolymerization in the Presence of Multiwalled Carbon Nanotubes: Toward 3D Printing Conducting Nanocomposites,” ACS Macro Lett. 11(3), 303–309 (2022). [CrossRef]
44. G. Yang, Y. Sun, Q. Limin, M. Li, K. Ou, J. Fang, and Q. Fu, “Direct-ink-writing (DIW) 3D printing functional composite materials based on supra-molecular interaction,” Compos. Sci. Technol. 215, 109013 (2021). [CrossRef]
45. R. N. Sampaio, D. C. Grills, D. E. Polyansky, D. J. Szalda, and E. Fujita, “Unexpected Roles of Triethanolamine in the Photochemical Reduction of CO2 to Formate by Ruthenium Complexes,” J. Am. Chem. Soc. 142(5), 2413–2428 (2020). [CrossRef]
46. Y. Al-Hadeethi, E. M. Mkawi, O. Al-Hartomy, and E. Bekyarova, “Role of triethanolamine in forming Cu2ZnSnS4 nanoparticles during solvothermal processing for solar cell applications,” Int. J. Energy Res. 46(6), 7239–7248 (2022). [CrossRef]
47. W. Zhang, Y. Yu, R. Huang, and X. Shi, “Efficient Photocatalytic Reduction of CO2 to CO Using NiFe2O4@N/C/SnO2 Derived from FeNi Metal-Organic Framework,” ACS Appl. Mater. Interfaces 13(34), 40571–40581 (2021). [CrossRef]
48. Y. Wang, Q. Yang, F. Yi, R. Lu, Y. Chen, C. Liu, X. Li, C. Wang, and H. Yan, “NH2-UiO-66 Coated with Two-Dimensional Covalent Organic Frameworks: High Stability and Photocatalytic Activity,” ACS Appl. Mater. Interfaces 13(25), 29916–29925 (2021). [CrossRef]
49. Q. Wang, Z. Fang, X. Zhao, C. Dong, Y. Li, C. Guo, Q. Liu, F. Song, and W. Zhang, “Biotemplated g-C3N4/Au Periodic Hierarchical Structures for the Enhancement of Photocatalytic CO2 Reduction with Localized Surface Plasmon Resonance,” ACS Appl. Mater. Interfaces 13(50), 59855–59866 (2021). [CrossRef]
50. J. Zhu, G. Wang, Y. Hao, B. Xie, and A. Y. S. Cheng, “Highly sensitive and spatially resolved polyvinyl alcohol/acrylamide photopolymer for real-time holographic applications,” Opt. Express 18(17), 18106–18112 (2010). [CrossRef]
51. T. Mikulchyk, J. Walshe, D. Cody, S. Martin, and I. Naydenova, “Humidity and temperature induced changes in the diffraction efficiency and the Bragg angle of slanted photopolymer-based holographic gratings,” Sens. Actuators B 239, 776–785 (2017). [CrossRef]
52. D. Missirlis, M. Banos, F. Lussier, and J. P. Spatz, “Facile and Versatile Method for Micropatterning Poly(acrylamide) Hydrogels Using Photocleavable Comonomers,” ACS Appl. Mater. Interfaces 14(3), 3643–3652 (2022). [CrossRef]
53. I. Naydenova, E. Mihaylova, S. Martin, and V. Toal, “Holographic patterning of acrylamide–based photopolymer surface,” Opt. Express 13(13), 4878–4889 (2005). [CrossRef]
54. P. Hu, J. Li, J. Jin, X. Lin, and X. Tan, “Highly Sensitive Photopolymer for Holographic Data Storage Containing Methacryl Polyhedral Oligomeric Silsesquioxane,” ACS Appl. Mater. Interfaces (2022).
55. M. Omichi, H. Marui, K. Takano, S. Tsukuda, M. Sugimoto, S. Kuwabata, and S. Seki, “Temperature-responsive one-dimensional nanogels formed by the cross-linker-aided single particle nanofabrication technique,” ACS Appl. Mater. Interfaces 4(10), 5492–5497 (2012). [CrossRef]
56. D. Das, P. Ghosh, A. Ghosh, C. Haldar, S. Dhara, A. B. Panda, and S. Pal, “Stimulus-Responsive, Biodegradable, Biocompatible, Covalently Cross-Linked Hydrogel Based on Dextrin and Poly(N-isopropylacrylamide) for in Vitro/in Vivo Controlled Drug Release,” ACS Appl. Mater. Interfaces 7(26), 14338–14351 (2015). [CrossRef]
57. R. Tabatabaeian, M. Dinari, and H. M. Aliabadi, “Cross-linked bionanocomposites of hydrolyzed guar gum/magnetic layered double hydroxide as an effective sorbent for methylene blue removal,” Carbohydr. Polym. 257, 117628 (2021). [CrossRef]
58. R. Castagna, F. Vita, D. E. Lucchetta, L. Criante, and F. Simoni, “Superior-Performance Polymeric Composite Materials for High-Density Optical Data Storage,” Adv. Mater. 21(5), 589–592 (2009). [CrossRef]
59. Y. Liu, F. Fan, Y. Hong, J. Zang, G. Kang, and X. Tan, “Volume holographic recording in Irgacure 784-doped PMMA photopolymer,” Opt. Express 25(17), 20654–20662 (2017). [CrossRef]
60. Y.-C. Jeong, S. Lee, and J.-K. Park, “Holographic diffraction gratings with enhanced sensitivity based on epoxy-resin photopolymers,” Opt. Express 15(4), 1497–1504 (2007). [CrossRef]
61. H. Peng, C. Wang, W. Xi, B. A. Kowalsk, T. Gong, X. Xie, W. Wang, D. P. Nair, R. R. McLeod, and C. N. Bowman, “Facile image patterning via sequential thiol–Michael-thiol–yne click reactions,” Chem. Mater. 26(23), 6819–6826 (2014). [CrossRef]
