High-sensitivity Goos-Hanchen shift gas sensor based on subwavelength hyperbolic metamaterials

Optical gas sensors play an increasingly important role in many applications, particularly for the detection of toxic gases. A novel Goos-Hanchen (GH) shift optical gas sensing scheme based on subwavelength hyperbolic metamaterials (HMMs) is proposed. The GH shift intensity, direction and the critical wavelength characteristics were revealed. By virtue of the GH shift and subwavelength HMMs characteristics, we designed an ultra-sensitive gas sensor to detect helium (He), hydrogen (H-2), carbon monoxide (CO) and methane (CH4). The study shows that the sensitivities of the gas sensor can reach as high as S-He= 3.06 x10(6 )mu m/RIU, S-H2 = 2.86 x 10(6 )mu m/RIU, S-CO = 1.81 x 10(6 )mu m/RIU, and S-CH4 = 9.58 x 10(5 )mu m/RIU. With proper surface chemical modification, this GH shift gas sensor would be a powerful tool for high-sensitive gas sensing applications.