一种高通量宽带近红外声光可调滤光器的设计

声光可调滤光器(AOTF)是20世纪90年代以来近红外光谱仪最突出的进展，传统的单换能器结构使滤光器存在工作带宽较窄的问题。本文采用双换能器结构设计了一种高通量、宽带宽的近红外声光可调滤光器，基于“切面平行条件”波矢量布局方案，通过仿真计算确定声光晶体最优切向切角及换能器长度等最佳参数。两段换能器分别工作于两个不同的波段范围，使得滤光器的工作波段范围在光谱分辨率、衍射效率等参数满足要求的前提下大为改善。测试结果表明，设计的滤光器在900～2 400 nm波段范围内分辨率优于15 nm，衍射效率最高可到41%。

Design of a High-Throughput and Wide-Bandwidth Near-Infrared Acousto-Optic Tunable Filter

The acousto-optic tunable filter (AOTF) is the most outstanding progress of near-infrared spectrometer since the 1990s. Restriction in working range and performance of the device exists due to the traditional single-transducer structure. The design of a near-infrared acousto-optic tunable filter with high-throughput and wide-bandwidth adopting a dual-transducer structure is reported in the present paper. By calculation and simulation based on the wave vector diagram which satisfies the parallel-tangents condition, the optimal cutting direction and cutting angle of the acousto-optic crystal, the length of the transducers and other best parameters were obtained. The tuning range of the filter is improved significantly while the resolution, diffraction efficiency and other parameters satisfy the requirements by making two transducers working at the high-frequency part and low-frequency part respectively．According to the testing results of the designed filter, the spectrum resolution is better than 15 nm and the diffraction efficiency is reaches to 41% with the tuning range of 900～2 400 nm.