Low-index-mode photonic crystal nanobeam cavity for refractive index sensing at the 2 μm wavelength band

We present the design, fabrication, and characterization of a one-dimensional photonic crystal (1D-PhC) low-index-mode nanobeam cavity on the silicon-on-insulator platform for refractive index sensing at the 2 mu m wavelength band. A Q-factor of 4.35 x 10(5 )and an effective mode volume of V-eff similar to 1.95(lambda/n(si))(3) are theoretically achieved. The measured transmission spectrum of the device immersed in NaCI solutions with different mass concentrations demonstrates a sensitivity of 326.1 nm/RIU and a Q-factor of similar to 1144. (C) 2019 Optical Society of America