[11a-W935-1~10] 3.8 Optical measurement, instrumentation, and sensor

▼ [11a-W935-4] Proposal of Two Tangent Hole Structure for Higher Sensitivity Gas Sensor

〇(D)ZANHUI CHEN¹, Wenying Li¹, Yu Han¹, Haisong Jiang¹, Kiichi Hamamoto¹ (1.Kyushu Univ.)

Keywords:Silicon PhC cavity-based on Gas sensor

Silicon photonic crystal cavities (PhC) with high-quality factors are very sensitive to the changes in the dielectric properties of their surroundings. Utilizing this high sensitivity, it is used for the ultrasensitive gas sensor, One problem, however, for typical PhC structures, the sensitivity (S) is low because the analyte is located in the air or liquid region where the strength of the confined light field fully overlaps with the analyte. Therefore, the gas detection sensitivities of most geometries are generally limited to around 0.3-0.67 nm/%. To overcome this problem, we propose a photonic crystal cavity consisting of a bus waveguide and the tangent air hole array. Based on this design, which tightly confines light in the air region where it fully overlaps with gas molecules, to improve the gas detection sensitivity. Theoretical analysis reveals that methane gas detection sensitivity significantly improved to 2.16 nm/%.