上海科技大学知识管理系统

The dual-color (dual band-pass) filter is a new type of optical element that includes two precisely controlled spectral channels at any geometric position and can improve the target recognition ability of optical detection devices. Single crystal Ge is used as a substrate, and Ge and ZnSe are used as high (H) and low (L) reflective index thin film materials, respectively. An infrared dual-color filter is designed with two band-pass channels: 3.2~3.8 μm (channel 1) and 4.9~5.4 μm (channel 2). Thin films are fabricated by thermal evaporation in a high vacuum chamber, and the film thickness are monitored using the POEM (Percent of Optical Extreme Monitoring) strategy. At a working temperature of 100 K, the average transmittance of channel 1 was 94.2%, and its top ripple amplitude was 5.7%; the average transmittance of channel 2 was 96.5%, and its top ripple amplitude was 0.6%. In the cut-off range between the two channels (4.0~4.7 μm), the average transmittance was no more than 0.16%. The infrared dual-color filter has good optical stability, which is conducive to the recognition of high-speed moving targets. Copyright ©2021 Chinese Optics. All rights reserved.