Abstract

A low-cost humidity and pressure optical sensor, based on the internal reflection phenomenon, is presented. It takes advantage of the phase difference acquired by s- and p-polarized light undergoing internal reflection to generate an easily detectable minimum in the reflected profile, in a position corresponding to the critical angle. The apparatus presents good sensitivity to relative humidity changes above 70% and a response time below one second. The same device is also capable of measuring changes in pressure and can be used as a vacuum gauge between 1 and 1000 mbar.

© 2014 Optical Society of America

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References

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  1. Z. Chen and C. Lu, “Humidity sensors: a review of materials and mechanisms,” Sens. Lett. 3, 274–295 (2005).
    [CrossRef]
  2. C.-Y. Lee, “Humidity sensors: a review,” Sens. Lett. 3, 1–15 (2005).
    [CrossRef]
  3. H. Y. Wang, Y. Q. Wang, Q. F. Hua, and X. J. Li, “Capacitive humidity sensing properties of SiC nanowires grown on silicon nanoporous pillar array,” Sens. Actuators B 166, 451–456 (2012).
    [CrossRef]
  4. J. J. Steele, M. T. Taschuk, and M. J. Brett, “Response time of nanostructured relative humidity sensors,” Sens. Actuators B 140, 610–615 (2009).
    [CrossRef]
  5. A. Buvailo, Y. Xing, J. Hines, and E. Borguet, “Thin polymer film based rapid surface acoustic wave humidity sensors,” Sens. Actuators B 156, 444–449 (2011).
    [CrossRef]
  6. Y. Li, C. Deng, and M. Yang, “A novel surface acoustic wave-impedance humidity sensor based on the composite of polyaniline and poly(vinyl alcohol) with a capability of detecting low humidity,” Sens. Actuators B 165, 7–12 (2012).
    [CrossRef]
  7. Y. J. Liu, J. Shi, F. Zhang, H. Liang, J. Xu, A. Lakhtakia, S. J. Fonash, and T. J. Huang, “High-speed optical humidity sensors based on chiral sculptured thin films,” Sensor Actuat. B 156, 593–598 (2011).
    [CrossRef]
  8. L. H. Chen, T. Li, C. C. Chana, R. Menon, P. Balamurali, M. Shaillender, B. Neu, X. M. Ang, P. Zu, W. C. Wong, and K. C. Leong, “Chitosan-based fiber optic Fabry–Perot humidity sensor,” Sens. Actuators B 169, 167–172 (2012).
    [CrossRef]
  9. B. C. Yadav, N. Verma, and S. Singh, “Nanocrystalline SnO2–TiO2 thin film deposited on base of equilateral prism as an opto-electronic humidity sensor,” Opt. Laser Technol. 44, 1681–1688 (2012).
    [CrossRef]
  10. P. Egan and J. A. Stone, “Absolute refractometry of dry gas to ±3 parts in 109,” Appl. Opt. 50, 3076–3086 (2011).
    [CrossRef]
  11. J. Zhang, Z. H. Lu, B. Menegozzi, and L. J. Wang, “Application of frequency combs in the measurement of the refractive index of air,” Rev. Sci. Instrum. 77, 083104 (2006).
    [CrossRef]
  12. S. C. Zilio, “A simple method to measure critical angles for high-sensitivity differential refractometry,” Opt. Express 20, 1862–1867 (2012).
    [CrossRef]
  13. J. A. Stone and J. H. Zimmerman, “Refractive index of air calculator,” Available in: http://emtoolbox.nist.gov/Wavelength/Edlen.asp .
  14. T. G. Beckwith, R. D. Marangoni, and J. H. Lienhard, Mechanical Measurements, 5th ed. (Addison–Wesley, 1993), pp. 591–595.
  15. R. A. S. Ribeiro, J. F. M. Domenegueti, and S. C. Zilio, “High-sensitivity optical humidity sensor based on a thin dielectric waveguide,” Appl. Opt. 52, 4287–4293 (2013).
    [CrossRef]
  16. G. R. Fowles, Introduction to Modern Optics (Holt, Rinehart and Winston, 1968).
  17. D. B. Asay and S. H. Kim, “Evolution of the adsorbed water layer structure on silicon oxide at room temperature,” J. Phys. Chem. B 109, 16760–16763 (2005).
    [CrossRef]
  18. W. Ecke, A. A. Chertoriiski, and V. L. Vesnin, “A high-speed system for strain and temperature measurements based on fiber Bragg sensors,” Instrum. Exp. Tech. 50, 565–571 (2007).
    [CrossRef]

2013 (1)

2012 (5)

S. C. Zilio, “A simple method to measure critical angles for high-sensitivity differential refractometry,” Opt. Express 20, 1862–1867 (2012).
[CrossRef]

Y. Li, C. Deng, and M. Yang, “A novel surface acoustic wave-impedance humidity sensor based on the composite of polyaniline and poly(vinyl alcohol) with a capability of detecting low humidity,” Sens. Actuators B 165, 7–12 (2012).
[CrossRef]

H. Y. Wang, Y. Q. Wang, Q. F. Hua, and X. J. Li, “Capacitive humidity sensing properties of SiC nanowires grown on silicon nanoporous pillar array,” Sens. Actuators B 166, 451–456 (2012).
[CrossRef]

L. H. Chen, T. Li, C. C. Chana, R. Menon, P. Balamurali, M. Shaillender, B. Neu, X. M. Ang, P. Zu, W. C. Wong, and K. C. Leong, “Chitosan-based fiber optic Fabry–Perot humidity sensor,” Sens. Actuators B 169, 167–172 (2012).
[CrossRef]

B. C. Yadav, N. Verma, and S. Singh, “Nanocrystalline SnO2–TiO2 thin film deposited on base of equilateral prism as an opto-electronic humidity sensor,” Opt. Laser Technol. 44, 1681–1688 (2012).
[CrossRef]

2011 (3)

Y. J. Liu, J. Shi, F. Zhang, H. Liang, J. Xu, A. Lakhtakia, S. J. Fonash, and T. J. Huang, “High-speed optical humidity sensors based on chiral sculptured thin films,” Sensor Actuat. B 156, 593–598 (2011).
[CrossRef]

A. Buvailo, Y. Xing, J. Hines, and E. Borguet, “Thin polymer film based rapid surface acoustic wave humidity sensors,” Sens. Actuators B 156, 444–449 (2011).
[CrossRef]

P. Egan and J. A. Stone, “Absolute refractometry of dry gas to ±3 parts in 109,” Appl. Opt. 50, 3076–3086 (2011).
[CrossRef]

2009 (1)

J. J. Steele, M. T. Taschuk, and M. J. Brett, “Response time of nanostructured relative humidity sensors,” Sens. Actuators B 140, 610–615 (2009).
[CrossRef]

2007 (1)

W. Ecke, A. A. Chertoriiski, and V. L. Vesnin, “A high-speed system for strain and temperature measurements based on fiber Bragg sensors,” Instrum. Exp. Tech. 50, 565–571 (2007).
[CrossRef]

2006 (1)

J. Zhang, Z. H. Lu, B. Menegozzi, and L. J. Wang, “Application of frequency combs in the measurement of the refractive index of air,” Rev. Sci. Instrum. 77, 083104 (2006).
[CrossRef]

2005 (3)

D. B. Asay and S. H. Kim, “Evolution of the adsorbed water layer structure on silicon oxide at room temperature,” J. Phys. Chem. B 109, 16760–16763 (2005).
[CrossRef]

Z. Chen and C. Lu, “Humidity sensors: a review of materials and mechanisms,” Sens. Lett. 3, 274–295 (2005).
[CrossRef]

C.-Y. Lee, “Humidity sensors: a review,” Sens. Lett. 3, 1–15 (2005).
[CrossRef]

Ang, X. M.

L. H. Chen, T. Li, C. C. Chana, R. Menon, P. Balamurali, M. Shaillender, B. Neu, X. M. Ang, P. Zu, W. C. Wong, and K. C. Leong, “Chitosan-based fiber optic Fabry–Perot humidity sensor,” Sens. Actuators B 169, 167–172 (2012).
[CrossRef]

Asay, D. B.

D. B. Asay and S. H. Kim, “Evolution of the adsorbed water layer structure on silicon oxide at room temperature,” J. Phys. Chem. B 109, 16760–16763 (2005).
[CrossRef]

Balamurali, P.

L. H. Chen, T. Li, C. C. Chana, R. Menon, P. Balamurali, M. Shaillender, B. Neu, X. M. Ang, P. Zu, W. C. Wong, and K. C. Leong, “Chitosan-based fiber optic Fabry–Perot humidity sensor,” Sens. Actuators B 169, 167–172 (2012).
[CrossRef]

Beckwith, T. G.

T. G. Beckwith, R. D. Marangoni, and J. H. Lienhard, Mechanical Measurements, 5th ed. (Addison–Wesley, 1993), pp. 591–595.

Borguet, E.

A. Buvailo, Y. Xing, J. Hines, and E. Borguet, “Thin polymer film based rapid surface acoustic wave humidity sensors,” Sens. Actuators B 156, 444–449 (2011).
[CrossRef]

Brett, M. J.

J. J. Steele, M. T. Taschuk, and M. J. Brett, “Response time of nanostructured relative humidity sensors,” Sens. Actuators B 140, 610–615 (2009).
[CrossRef]

Buvailo, A.

A. Buvailo, Y. Xing, J. Hines, and E. Borguet, “Thin polymer film based rapid surface acoustic wave humidity sensors,” Sens. Actuators B 156, 444–449 (2011).
[CrossRef]

Chana, C. C.

L. H. Chen, T. Li, C. C. Chana, R. Menon, P. Balamurali, M. Shaillender, B. Neu, X. M. Ang, P. Zu, W. C. Wong, and K. C. Leong, “Chitosan-based fiber optic Fabry–Perot humidity sensor,” Sens. Actuators B 169, 167–172 (2012).
[CrossRef]

Chen, L. H.

L. H. Chen, T. Li, C. C. Chana, R. Menon, P. Balamurali, M. Shaillender, B. Neu, X. M. Ang, P. Zu, W. C. Wong, and K. C. Leong, “Chitosan-based fiber optic Fabry–Perot humidity sensor,” Sens. Actuators B 169, 167–172 (2012).
[CrossRef]

Chen, Z.

Z. Chen and C. Lu, “Humidity sensors: a review of materials and mechanisms,” Sens. Lett. 3, 274–295 (2005).
[CrossRef]

Chertoriiski, A. A.

W. Ecke, A. A. Chertoriiski, and V. L. Vesnin, “A high-speed system for strain and temperature measurements based on fiber Bragg sensors,” Instrum. Exp. Tech. 50, 565–571 (2007).
[CrossRef]

Deng, C.

Y. Li, C. Deng, and M. Yang, “A novel surface acoustic wave-impedance humidity sensor based on the composite of polyaniline and poly(vinyl alcohol) with a capability of detecting low humidity,” Sens. Actuators B 165, 7–12 (2012).
[CrossRef]

Domenegueti, J. F. M.

Ecke, W.

W. Ecke, A. A. Chertoriiski, and V. L. Vesnin, “A high-speed system for strain and temperature measurements based on fiber Bragg sensors,” Instrum. Exp. Tech. 50, 565–571 (2007).
[CrossRef]

Egan, P.

Fonash, S. J.

Y. J. Liu, J. Shi, F. Zhang, H. Liang, J. Xu, A. Lakhtakia, S. J. Fonash, and T. J. Huang, “High-speed optical humidity sensors based on chiral sculptured thin films,” Sensor Actuat. B 156, 593–598 (2011).
[CrossRef]

Fowles, G. R.

G. R. Fowles, Introduction to Modern Optics (Holt, Rinehart and Winston, 1968).

Hines, J.

A. Buvailo, Y. Xing, J. Hines, and E. Borguet, “Thin polymer film based rapid surface acoustic wave humidity sensors,” Sens. Actuators B 156, 444–449 (2011).
[CrossRef]

Hua, Q. F.

H. Y. Wang, Y. Q. Wang, Q. F. Hua, and X. J. Li, “Capacitive humidity sensing properties of SiC nanowires grown on silicon nanoporous pillar array,” Sens. Actuators B 166, 451–456 (2012).
[CrossRef]

Huang, T. J.

Y. J. Liu, J. Shi, F. Zhang, H. Liang, J. Xu, A. Lakhtakia, S. J. Fonash, and T. J. Huang, “High-speed optical humidity sensors based on chiral sculptured thin films,” Sensor Actuat. B 156, 593–598 (2011).
[CrossRef]

Kim, S. H.

D. B. Asay and S. H. Kim, “Evolution of the adsorbed water layer structure on silicon oxide at room temperature,” J. Phys. Chem. B 109, 16760–16763 (2005).
[CrossRef]

Lakhtakia, A.

Y. J. Liu, J. Shi, F. Zhang, H. Liang, J. Xu, A. Lakhtakia, S. J. Fonash, and T. J. Huang, “High-speed optical humidity sensors based on chiral sculptured thin films,” Sensor Actuat. B 156, 593–598 (2011).
[CrossRef]

Lee, C.-Y.

C.-Y. Lee, “Humidity sensors: a review,” Sens. Lett. 3, 1–15 (2005).
[CrossRef]

Leong, K. C.

L. H. Chen, T. Li, C. C. Chana, R. Menon, P. Balamurali, M. Shaillender, B. Neu, X. M. Ang, P. Zu, W. C. Wong, and K. C. Leong, “Chitosan-based fiber optic Fabry–Perot humidity sensor,” Sens. Actuators B 169, 167–172 (2012).
[CrossRef]

Li, T.

L. H. Chen, T. Li, C. C. Chana, R. Menon, P. Balamurali, M. Shaillender, B. Neu, X. M. Ang, P. Zu, W. C. Wong, and K. C. Leong, “Chitosan-based fiber optic Fabry–Perot humidity sensor,” Sens. Actuators B 169, 167–172 (2012).
[CrossRef]

Li, X. J.

H. Y. Wang, Y. Q. Wang, Q. F. Hua, and X. J. Li, “Capacitive humidity sensing properties of SiC nanowires grown on silicon nanoporous pillar array,” Sens. Actuators B 166, 451–456 (2012).
[CrossRef]

Li, Y.

Y. Li, C. Deng, and M. Yang, “A novel surface acoustic wave-impedance humidity sensor based on the composite of polyaniline and poly(vinyl alcohol) with a capability of detecting low humidity,” Sens. Actuators B 165, 7–12 (2012).
[CrossRef]

Liang, H.

Y. J. Liu, J. Shi, F. Zhang, H. Liang, J. Xu, A. Lakhtakia, S. J. Fonash, and T. J. Huang, “High-speed optical humidity sensors based on chiral sculptured thin films,” Sensor Actuat. B 156, 593–598 (2011).
[CrossRef]

Lienhard, J. H.

T. G. Beckwith, R. D. Marangoni, and J. H. Lienhard, Mechanical Measurements, 5th ed. (Addison–Wesley, 1993), pp. 591–595.

Liu, Y. J.

Y. J. Liu, J. Shi, F. Zhang, H. Liang, J. Xu, A. Lakhtakia, S. J. Fonash, and T. J. Huang, “High-speed optical humidity sensors based on chiral sculptured thin films,” Sensor Actuat. B 156, 593–598 (2011).
[CrossRef]

Lu, C.

Z. Chen and C. Lu, “Humidity sensors: a review of materials and mechanisms,” Sens. Lett. 3, 274–295 (2005).
[CrossRef]

Lu, Z. H.

J. Zhang, Z. H. Lu, B. Menegozzi, and L. J. Wang, “Application of frequency combs in the measurement of the refractive index of air,” Rev. Sci. Instrum. 77, 083104 (2006).
[CrossRef]

Marangoni, R. D.

T. G. Beckwith, R. D. Marangoni, and J. H. Lienhard, Mechanical Measurements, 5th ed. (Addison–Wesley, 1993), pp. 591–595.

Menegozzi, B.

J. Zhang, Z. H. Lu, B. Menegozzi, and L. J. Wang, “Application of frequency combs in the measurement of the refractive index of air,” Rev. Sci. Instrum. 77, 083104 (2006).
[CrossRef]

Menon, R.

L. H. Chen, T. Li, C. C. Chana, R. Menon, P. Balamurali, M. Shaillender, B. Neu, X. M. Ang, P. Zu, W. C. Wong, and K. C. Leong, “Chitosan-based fiber optic Fabry–Perot humidity sensor,” Sens. Actuators B 169, 167–172 (2012).
[CrossRef]

Neu, B.

L. H. Chen, T. Li, C. C. Chana, R. Menon, P. Balamurali, M. Shaillender, B. Neu, X. M. Ang, P. Zu, W. C. Wong, and K. C. Leong, “Chitosan-based fiber optic Fabry–Perot humidity sensor,” Sens. Actuators B 169, 167–172 (2012).
[CrossRef]

Ribeiro, R. A. S.

Shaillender, M.

L. H. Chen, T. Li, C. C. Chana, R. Menon, P. Balamurali, M. Shaillender, B. Neu, X. M. Ang, P. Zu, W. C. Wong, and K. C. Leong, “Chitosan-based fiber optic Fabry–Perot humidity sensor,” Sens. Actuators B 169, 167–172 (2012).
[CrossRef]

Shi, J.

Y. J. Liu, J. Shi, F. Zhang, H. Liang, J. Xu, A. Lakhtakia, S. J. Fonash, and T. J. Huang, “High-speed optical humidity sensors based on chiral sculptured thin films,” Sensor Actuat. B 156, 593–598 (2011).
[CrossRef]

Singh, S.

B. C. Yadav, N. Verma, and S. Singh, “Nanocrystalline SnO2–TiO2 thin film deposited on base of equilateral prism as an opto-electronic humidity sensor,” Opt. Laser Technol. 44, 1681–1688 (2012).
[CrossRef]

Steele, J. J.

J. J. Steele, M. T. Taschuk, and M. J. Brett, “Response time of nanostructured relative humidity sensors,” Sens. Actuators B 140, 610–615 (2009).
[CrossRef]

Stone, J. A.

Taschuk, M. T.

J. J. Steele, M. T. Taschuk, and M. J. Brett, “Response time of nanostructured relative humidity sensors,” Sens. Actuators B 140, 610–615 (2009).
[CrossRef]

Verma, N.

B. C. Yadav, N. Verma, and S. Singh, “Nanocrystalline SnO2–TiO2 thin film deposited on base of equilateral prism as an opto-electronic humidity sensor,” Opt. Laser Technol. 44, 1681–1688 (2012).
[CrossRef]

Vesnin, V. L.

W. Ecke, A. A. Chertoriiski, and V. L. Vesnin, “A high-speed system for strain and temperature measurements based on fiber Bragg sensors,” Instrum. Exp. Tech. 50, 565–571 (2007).
[CrossRef]

Wang, H. Y.

H. Y. Wang, Y. Q. Wang, Q. F. Hua, and X. J. Li, “Capacitive humidity sensing properties of SiC nanowires grown on silicon nanoporous pillar array,” Sens. Actuators B 166, 451–456 (2012).
[CrossRef]

Wang, L. J.

J. Zhang, Z. H. Lu, B. Menegozzi, and L. J. Wang, “Application of frequency combs in the measurement of the refractive index of air,” Rev. Sci. Instrum. 77, 083104 (2006).
[CrossRef]

Wang, Y. Q.

H. Y. Wang, Y. Q. Wang, Q. F. Hua, and X. J. Li, “Capacitive humidity sensing properties of SiC nanowires grown on silicon nanoporous pillar array,” Sens. Actuators B 166, 451–456 (2012).
[CrossRef]

Wong, W. C.

L. H. Chen, T. Li, C. C. Chana, R. Menon, P. Balamurali, M. Shaillender, B. Neu, X. M. Ang, P. Zu, W. C. Wong, and K. C. Leong, “Chitosan-based fiber optic Fabry–Perot humidity sensor,” Sens. Actuators B 169, 167–172 (2012).
[CrossRef]

Xing, Y.

A. Buvailo, Y. Xing, J. Hines, and E. Borguet, “Thin polymer film based rapid surface acoustic wave humidity sensors,” Sens. Actuators B 156, 444–449 (2011).
[CrossRef]

Xu, J.

Y. J. Liu, J. Shi, F. Zhang, H. Liang, J. Xu, A. Lakhtakia, S. J. Fonash, and T. J. Huang, “High-speed optical humidity sensors based on chiral sculptured thin films,” Sensor Actuat. B 156, 593–598 (2011).
[CrossRef]

Yadav, B. C.

B. C. Yadav, N. Verma, and S. Singh, “Nanocrystalline SnO2–TiO2 thin film deposited on base of equilateral prism as an opto-electronic humidity sensor,” Opt. Laser Technol. 44, 1681–1688 (2012).
[CrossRef]

Yang, M.

Y. Li, C. Deng, and M. Yang, “A novel surface acoustic wave-impedance humidity sensor based on the composite of polyaniline and poly(vinyl alcohol) with a capability of detecting low humidity,” Sens. Actuators B 165, 7–12 (2012).
[CrossRef]

Zhang, F.

Y. J. Liu, J. Shi, F. Zhang, H. Liang, J. Xu, A. Lakhtakia, S. J. Fonash, and T. J. Huang, “High-speed optical humidity sensors based on chiral sculptured thin films,” Sensor Actuat. B 156, 593–598 (2011).
[CrossRef]

Zhang, J.

J. Zhang, Z. H. Lu, B. Menegozzi, and L. J. Wang, “Application of frequency combs in the measurement of the refractive index of air,” Rev. Sci. Instrum. 77, 083104 (2006).
[CrossRef]

Zilio, S. C.

Zu, P.

L. H. Chen, T. Li, C. C. Chana, R. Menon, P. Balamurali, M. Shaillender, B. Neu, X. M. Ang, P. Zu, W. C. Wong, and K. C. Leong, “Chitosan-based fiber optic Fabry–Perot humidity sensor,” Sens. Actuators B 169, 167–172 (2012).
[CrossRef]

Appl. Opt. (2)

Instrum. Exp. Tech. (1)

W. Ecke, A. A. Chertoriiski, and V. L. Vesnin, “A high-speed system for strain and temperature measurements based on fiber Bragg sensors,” Instrum. Exp. Tech. 50, 565–571 (2007).
[CrossRef]

J. Phys. Chem. B (1)

D. B. Asay and S. H. Kim, “Evolution of the adsorbed water layer structure on silicon oxide at room temperature,” J. Phys. Chem. B 109, 16760–16763 (2005).
[CrossRef]

Opt. Express (1)

Opt. Laser Technol. (1)

B. C. Yadav, N. Verma, and S. Singh, “Nanocrystalline SnO2–TiO2 thin film deposited on base of equilateral prism as an opto-electronic humidity sensor,” Opt. Laser Technol. 44, 1681–1688 (2012).
[CrossRef]

Rev. Sci. Instrum. (1)

J. Zhang, Z. H. Lu, B. Menegozzi, and L. J. Wang, “Application of frequency combs in the measurement of the refractive index of air,” Rev. Sci. Instrum. 77, 083104 (2006).
[CrossRef]

Sens. Actuators B (5)

H. Y. Wang, Y. Q. Wang, Q. F. Hua, and X. J. Li, “Capacitive humidity sensing properties of SiC nanowires grown on silicon nanoporous pillar array,” Sens. Actuators B 166, 451–456 (2012).
[CrossRef]

J. J. Steele, M. T. Taschuk, and M. J. Brett, “Response time of nanostructured relative humidity sensors,” Sens. Actuators B 140, 610–615 (2009).
[CrossRef]

A. Buvailo, Y. Xing, J. Hines, and E. Borguet, “Thin polymer film based rapid surface acoustic wave humidity sensors,” Sens. Actuators B 156, 444–449 (2011).
[CrossRef]

Y. Li, C. Deng, and M. Yang, “A novel surface acoustic wave-impedance humidity sensor based on the composite of polyaniline and poly(vinyl alcohol) with a capability of detecting low humidity,” Sens. Actuators B 165, 7–12 (2012).
[CrossRef]

L. H. Chen, T. Li, C. C. Chana, R. Menon, P. Balamurali, M. Shaillender, B. Neu, X. M. Ang, P. Zu, W. C. Wong, and K. C. Leong, “Chitosan-based fiber optic Fabry–Perot humidity sensor,” Sens. Actuators B 169, 167–172 (2012).
[CrossRef]

Sens. Lett. (2)

Z. Chen and C. Lu, “Humidity sensors: a review of materials and mechanisms,” Sens. Lett. 3, 274–295 (2005).
[CrossRef]

C.-Y. Lee, “Humidity sensors: a review,” Sens. Lett. 3, 1–15 (2005).
[CrossRef]

Sensor Actuat. B (1)

Y. J. Liu, J. Shi, F. Zhang, H. Liang, J. Xu, A. Lakhtakia, S. J. Fonash, and T. J. Huang, “High-speed optical humidity sensors based on chiral sculptured thin films,” Sensor Actuat. B 156, 593–598 (2011).
[CrossRef]

Other (3)

J. A. Stone and J. H. Zimmerman, “Refractive index of air calculator,” Available in: http://emtoolbox.nist.gov/Wavelength/Edlen.asp .

T. G. Beckwith, R. D. Marangoni, and J. H. Lienhard, Mechanical Measurements, 5th ed. (Addison–Wesley, 1993), pp. 591–595.

G. R. Fowles, Introduction to Modern Optics (Holt, Rinehart and Winston, 1968).

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Figures (7)

Fig. 1.
Fig. 1.

Optical layout of setup used for the internal reflection-based RH and vacuum sensor. The dimensions are not to scale.

Fig. 2.
Fig. 2.

(a) Amplitude and (b) phase difference of components with polarizations s and p, together with (c) the intensity transmitted through the analyzer.

Fig. 3.
Fig. 3.

Image obtained with a Web camera for attenuated laser power. (a) Intensity profile measured by the CCD linear array at lower (b) and higher (c) laser powers.

Fig. 4.
Fig. 4.

(a) Home-made humidity chamber and (b) Pyrex bell jar used for the measurement of primary vacuum.

Fig. 5.
Fig. 5.

Position of the minimum of the reflected profile as a function of RH at 22°C. The solid line is the fit achieved with an exponential growth function and the error bars are given by the uncertainty of the commercial sensor.

Fig. 6.
Fig. 6.

Transient response between 45% and 90% RH for time periods of (a) 60 s and (b) 6 s.

Fig. 7.
Fig. 7.

Measurement result with the primary vacuum device measuring the critical angle. The upper abscissa is the RI.

Equations (3)

Equations on this page are rendered with MathJax. Learn more.

rs=cosθn2sen2θcosθ+n2sen2θ,
rp=n2cosθ+n2sen2θn2cosθ+n2sen2θ,
I=I0(|rs|2+|rp|2+2|rs||rs|cosφ),

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