Suhre Dennis R, Gupta Neelam
Carnegie Mellon University, 700 Technology Drive, Pittsburgh, Pennsylvania 15219-3124, USA.
Appl Opt. 2005 Sep 20;44(27):5797-801. doi: 10.1364/ao.44.005797.
The acousto-optic tunable filter (AOTF) has optical sidelobes that are due to the acoustic field produced by the transducer. These sidelobes were analyzed by wave-vector phase matching between the optical and acoustic fields, which correlated with measurements made with a TeO2 AOTF. A white-light point source was filtered and imaged, showing reasonably large and slowly decreasing sidelobes covering a large spectral range. This effect reduces the image quality of an AOTF system by producing faint secondary images of bright objects. The image quality can be improved with a telecentric confocal optical arrangement in which the angular shift of the sidelobes is greatly reduced, producing a much sharper image. This effect was also demonstrated experimentally with the point source.
声光可调滤波器（AOTF）具有光学旁瓣，这是由换能器产生的声场所致。通过光场与声场之间的波矢相位匹配对这些旁瓣进行了分析，这与使用TeO2 AOTF进行的测量结果相关。对白光点光源进行滤波和成像，结果显示旁瓣相当大且衰减缓慢，覆盖了很大的光谱范围。这种效应通过产生明亮物体的微弱二次图像降低了AOTF系统的图像质量。采用远心共焦光学装置可提高图像质量，在该装置中旁瓣的角位移大大减小，从而产生更清晰的图像。使用点光源也通过实验证明了这种效应。
