Mid-infrared gas sensor based on high-Q/V point-defect photonic crystal nanocavities
Mid-infrared gas sensor based on high-Q/V point-defect photonic crystal nanocavities
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DOI：
10.1007/s11082-020-02366-w
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发表时间：
2020-05-08
影响因子：
3
通讯作者：
Cassan, Eric
中科院分区：
文献类型：
--
作者：
Kassa-Baghdouche, Lazhar;Cassan, Eric
对基于硅平面光子晶体（PhC）的点缺陷纳米腔进行了优化和研究，用于中红外波段气体折射率的传感。在由圆形气孔组成的光子晶体的三角形晶格中心引入点缺陷，使其适合探测腔内气体的性质。通过精确优化最靠近缺陷区域的空气孔的半径和位置，在几个纳米量级上，可以显著提高点缺陷PhC纳米空腔的质量因子与模态体积之比（Q/V）。此外，采用微扰方法研究了优化后的点缺陷纳米腔模式在气体折射率变化时的谐振波长偏移。结果表明，优化后的点缺陷PhC纳米腔的灵敏度为270 nm/RIU（折射率单位），检测限为10-4 RIU。这些纳米空腔被设计成具有高Q/V的单模振荡，从而能够以高灵敏度感知气体的折射率。
Point-defect nanocavities based on silicon planar photonic crystal (PhC) have been optimized and studied for sensing the refractive index of gases in the mid-infrared wavelength region. The point-defect has been introduced at the center of the triangular lattice of the photonic crystal that is made up of circular air holes, making it suitable for probing the properties of the gas found within the cavity. By optimizing the radius and position of the air holes closest to the defect region precisely, on the order of a few nanometers, the ratio of the quality factor to mode volume (Q/V) for the point-defect PhC nanocavities can be increased considerably. Moreover, a perturbation method has been implemented in order to study the resonant wavelength shift of the optimized point-defect nanocavity modes caused by a small change in the refractive index of the gas. The results obtained show that sensitivity of 270 nm/RIU (Refractive Index Unit) and a detection limit of 10-4 RIU can be achieved for the optimized point-defect PhC nanocavities. These nanocavities have been designed to oscillate at a single mode with a high Q/V thus enabling to sense the refractive index of gases with high sensitivity.