The excitation of surface plasmon on a metallic grating can be observed by varying the polar angle, accompanied by the absorption of incident light. The absorption occurs at a resonance angle which is sensitive to the refractive index of the liquid coated on the surface of the grating. As a result, an application in index sensing is developed. However, the sensitivity by varying the polar angle is almost at the same level as a conventional prism couple-based sensor through angular detection. In our new setup, we propose two methods to improve the sensitivity to refractive index change using an index sensor. Our first method is a slight modification of the conventional setup by varying the azimuth angle instead of the polar angle. Absorption of the incident is also observed while scanning the azimuth angle. The second method is to utilize phase detection to realize high resolution in finding the refractive index of liquids. In the phase detection, a good linearity is observed in the experimental results, with a resolution 10 times higher than that of a conventional setup.
"Improvement of Resolution of Liquid Refractive Index Measurement Using Metallic Grating," Progress In Electromagnetics Research M,
Vol. 85, 29-38, 2019. doi:10.2528/PIERM19060304
3. Barnes, W. L., T. W. Preist, S. C. Kitson, J. R. Sambles, N. P. K. Cotter, and D. J. Nash, "Photonic gaps in the dispersion of surface plasmons on gratings," Phys. Rev. B, Vol. 51, 11164-11167, 1995. doi:10.1103/PhysRevB.51.11164
4. Liu, L., L. Ran, H. Guo, X. Chen, and Z. Li, "Broadband plasmonic circuitry enabled by channel domino spoof plasmons," Progress In Electromagnetics Research, Vol. 164, 109-118, 2019. doi:10.2528/PIER18120502
5. Gifford, J. W. and T. M. Lowry, "Some refractive indices of benzene and cyclohexane," Proc. of the Royal Society of London, Series A, Vol. 104, No. 726, 430-437, 1923.
6. Thormahlen, I., J. Straub, and U. Grigull, "Refractive index of water and its dependence of wavelength, temperature, and density," J. Phys. Chem. Ref. Data, Vol. 14, No. 4, 1985. doi:10.1063/1.555743
7. Cheng, X. and B. Guan, "Optical biosensing and bioimaging with porous silicon and silicon quantum dots (Invited Review)," Progress In Electromagnetics Research, Vol. 160, 103-121, 2017. doi:10.2528/PIER17120504
8. He, S. and H. Dong, "Simultaneous estimation of the refractive index and thickness of marine oil slick from the degree of linear polarization of the sun-glint reflection," Progress In Electromagnetics Research, Vol. 163, 133-142, 2018. doi:10.2528/PIER18092601
9. Rossi, S., E. Gazzola, P. Capaldo, G. Borile, and F. Romanato, "Grating-coupled surface plasmon resonance (GC-SPR) optimization for phase-interrogation biosensing in a microfluidic chamber," Sensors (Basel), Vol. 18, No. 5, 1621, 2018. doi:10.3390/s18051621
10. Lu, H., Y. C. Fan, S. Q. Dai, D. Mao, F. J. Xiao, P. Li, and J. L. Zhao, "Coupling-induced spectral splitting for plasmonic sensing with ultra-high figure of merit," Chinese Physics B, Vol. 27, 117302, 2018. doi:10.1088/1674-1056/27/11/117302
11. Lu, H., S. Dai, Z. Yue, Y. Fan, H. Cheng, J. Di, D. Mao, E. Li, T. Mei, and J. Zhao, "Sb2Te3 topological insulator: Surface plasmon resonance and application in refractive index monitoring," Nanoscale, Vol. 11, 4759-4766, 2019. doi:10.1039/C8NR09227C
12. Okuno, Y., T. Suyama, and T. Matsuda, "Plasmon resonance-absorption in a dielectric coated metal grating," IEICE Trans. Electron., Vol. J88-C, No. 7, 582584, 2005 (in Japanese).
13. Okuno, Y., T. Suyama, R. Hu, S. He, and T. Matsuda, "Excitation of surface plasmons on a metal grating and its application to an index sensor," IEICE Trans. Electron., Vol. E90-C, No. 7, 1507-1514, 2007. doi:10.1093/ietele/e90-c.7.1507
14. Homola, J., S. Yee, and G. Gauglitz, "Surface plasmon resonance sensors: Review," Sensors and Actuators B, Vol. 54, 3-15, 1999. doi:10.1016/S0925-4005(98)00321-9
15. Homola, J., I. Koudela, and S. Yee, "Surface plasmon resonance sensors based on diffraction gratings and prism couplers: Sensitivity comparison," Sensors and Actuators B, Vol. 54, 16-24, 1999. doi:10.1016/S0925-4005(98)00322-0
16. Bryan-Brown, G. P., S. J. Elston, and J. R. Sambles, "Coupled surface plasmons on silver coated gratings," Opt. Commun., Vol. 82, 1-5, 1991. doi:10.1016/0030-4018(91)90180-L
17. Matsuda, T., D. Zhou, and Y. Okuno, "Numerical analysis of plasmon resonance absorption in bisinusoidal metal gratings," Journal of the Optical Society of America A, Vol. 19, No. 4, 695-701, 2002. doi:10.1364/JOSAA.19.000695
18. Okuno, Y. and T. Suyama, "Numerical analysis of surface plasmons excited on a thin metal grating," Journal of Zhejiang University SCIENCE A, Vol. 7, No. 1, 55-70, 2006. doi:10.1631/jzus.2006.A0055
19. Bryan-Brown, G. P., J. R. Sambles, and M. C. Hutley, "Polarization conversion through the excitation of surface plasmons on a metallic grating," J. Modern Optics, Vol. 37, No. 7, 1227-1232, 1990. doi:10.1080/09500349014551301
20. Matsuda, T., D. Zhou, and Y. Okuno, "Numerical analysis of TE-TM mode conversion in a metal grating placed in conical mounting," IEICE Trans. Electron., Vol. J82-C-I, No. 2, 42-49, 1999.
21. Hass, G. and L. Hadley, "Optical properties of metals," American Institute of Physics Handbook, 6-107, 1963.
22. Yasuura, K. and T. Itakura, "Approximation method for wave functions (I), (II), and (III)," Kyushu Univ. Tech. Rep., Vol. 39, No. 1, 51-56, 1966.
23. Yasuura, K., "A view of numerical methods in diffraction problems," Progress in Radio Science, 257-270, 1971.
24. Ikuno, H. and K. Yasuura, "Improved point-matching method with application to scattering from a periodic surface," IEEE Trams. Antennas & Propag., Vol. 21, 657-662, 1973. doi:10.1109/TAP.1973.1140592
25. Lawson, C. L. and R. J. Hanson, Solving Least-Squares Problems, Prentice-Hall, Englewood Cliffs, NJ, 1974.
26. Nelson, S. G., K. S. Johnston, and S. S. Yee, "High sensitivity surface plasmon resonance sensor based on phase detection," Sensors and Actuators B, Vol. 35, No. 1-3, 187-191, 1996. doi:10.1016/S0925-4005(97)80052-4
27. Law, W. C., P. Markowicz, K. T. Yong, I. Roy, A. Baev, S. Patskovsky, A. V. Kabashin, H. P. Ho, and P. N. Prasad, "Wide dynamic range phase-sensitive surface plasmon resonance biosensor based on measuring the modulation harmonics," Biosens. Bioelectron, Vol. 23, No. 5, 627-632, 2007. doi:10.1016/j.bios.2007.07.015
28. Luo, Z., T. Suyama, X. Xu, and Y. Okuno, "A grating-based plasmon biosensor with high resolution," Progress In Electromagnetics Research, Vol. 118, 527-539, 2011. doi:10.2528/PIER11060103
29. Budde, W., "Photoelectric analysis of polarized light," Opt., Vol. 1, 201-205, April 1962.
30. Horowitz, P. and W. Hill, The Art of Electronics, 641-646, Cambridge University Press, Cambridge, 1989.
31. Matsuda, T. and S. Hayashi, "Polarization of diffracted wave form periodic structures in resonance region," IEEJ, Vol. EMT-06-106, 115-119, 2006.
32. Lin, B. Q., J. Guo, Y. Wang, Z. Wang, B. Huang, and X. Liu, "A wide-angle and wide-band circular polarizer using a BI-Layer metasurface," Progress In Electromagnetics Research, Vol. 161, 125-133, 2018. doi:10.2528/PIER18010922