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摘要:双色滤光片在其任意一个几何位置上,均能够有效透过两个精确控制的光谱通道,它可以提升光学探测装置对目标的识别能力。本文选用单晶Ge作为基片,Ge和ZnSe分别作为高低折射率膜层材料,研制了一种包含3.2~3.8 μm(通道1)和4.9~5.4 μm(通道2)两个通道的红外双色滤光片。在高真空中以热蒸发的方式镀制了滤光片的光学膜层,采用单波长的极值百分比光学监控(POEM)方法控制膜层的光学厚度。在100 K低温下,通道1的平均透射率为94.2%,顶部波纹幅度为5.7%;通道2的平均透射率为96.5%,顶部波纹幅度为0.6%。在两个通道之间(4.0~4.7 μm)的截止区域内,平均透射率小于0.16%。该红外双色滤光片具有良好的光学稳定性,有利于高速运动目标的识别。Abstract: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.
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Key words:
- optical thin film/
- dual-color filter/
- infrared/
- cryogenic spectrum
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表 1Ge和ZnSe薄膜沉积工艺参数
Table 1.Deposition parameters of the Ge and ZnSe films
deposition rate/
(nm·s−1)chamber pressure/
(10−4Pa)rotation rate/
(rad·min−1)Ge layers 0.6 5~8 30 ZnSe layers 2 5~8 30 表 2两个通带的边缘陡度和顶部波纹振幅
Table 2.Edge steepness and top ripple amplitudes of the two channels
Edge steepness
of the left sideEdge steepness
of the right sideTop ripple
amplitudeChannel 1 (3.2~3.8 μm) 3.5% 2.1% 5.7% Channel 2 (4.9~5.4 μm) 2.7% 2.2% 0.6% 表 3温度由300 K变化至100 K时两个通带半峰波长位置的移动情况
Table 3.Half-peak wavelength point shift of the two channels when the temperature changes from 300 K to 100 K
(nm) Left sideT0.5P
wavelength point shiftRight sideT0.5P
wavelength point shiftChannel 1
(3.2~3.8 μm)−43 −49 Channel 2
(4.9~5.4 μm)−67 −73 -
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