新型宽带匹配网络在双路宽光谱声光可调谐滤光器成像技术中的应用

摘要

基于双路声光可调谐滤光器(AOTF)的宽光谱成像技术在偏振成像光谱仪中得到应用,其成像质量受AOTF衍射效率、光谱带宽等影响.其核心部件超声换能器阻抗失配时导致驱动功率无法最大限度地传递给换能器,使AOTF光谱衍射效率降低.3 dB光谱带宽变窄,影响光谱图像有用信息的获取.采用压缩回波损耗技术,设计了一种基于LC拓扑结构及组合臂的宽频带、光谱衍射效率高的新型匹配网络.最终测得AOTF的光谱衍射效率最高达94%,光谱带宽小于5 nm,提高了在420~1150 nm波段范围内的光谱衍射效率及分辨率,实测目标的成像质量得到明显改善.%Wide spectral imaging based on dual acousto-optic tunable filter(AOTF)is applied in polarimetric imaging spectrometers,and its image quality is affected by AOTF diffraction efficiency and spectral bandwidth.The core components of the ultrasonic transducer impedance mismatch leads to the drive power can not be the maximum transfer to the transducer,the AOTF spectral diffraction efficiency reduced,3 dB spectral bandwidth narrowed,af-fecting the spectral image useful information acquisition.A novel matching network with high bandwidth and high spectral efficiency based on LC topology and combined arm is designed by using compression loss technique.Final-ly,the spectral efficiency of AOTF is up to 94%,the spectral bandwidth is less than 5 nm,the spectral diffraction efficiency and resolution in the range of 420~1 150 nm are improved,and the imaging quality of the target is im-proved obviously.