为提高酒精检测系统的信噪比,根据比尔-朗伯定律确定双通窄带滤光片的技术参数;根据技术参数在Si基底上采用双面拆分法设计窄带滤光片,建立折射率渐变模型确定反演系数,实现膜层的准确控制。采用真空室原位退火法提高膜层聚集密度,降低膜层应力,进而提高膜层附着力,稳定膜层光谱性能;制备的膜层能够满足在(1392±10) nm和1530~1570 nm波段透射率大于90%,400~1350 nm和1600~1800 nm波段透射率小于1%,在1410~1515 nm波段透射率小于30%的要求。

To improve the signal-to-noise ratio of an alcohol vapor detection system, the technical parameters of a dual-pass narrow-band filter are determined according to the Beer-Lambert's law. The narrow-band filter is designed via double-sided splitting on a Si substrate according to technical parameters to establish the refractive index gradient model, realizing accurate control of films. The vacuum chamber in-situ annealing method is used to increase the density and reduce the stress of the film layer, thereby improving its adhesion and stabilizing its spectral properties. Of the prepared film layers, over 90% can satisfy transmittance at wavelengths of (1392±10) nm and 1530-1570 nm; less than 1% can satisfy 400-1350-nm and 1600-1800-nm band transmittances; the transmittance is less than 30% in the 1410-1515-nm band.