Acousto-optic tunable filter sidelobe analysis and reduction with telecentric confocal optics.
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.
Suhre
Dennis R
DR
Carnegie Mellon University, 700 Technology Drive, Pittsburgh, Pennsylvania 15219-3124, USA. dsuhre@andrew.cmu.edu
Gupta
Neelam
N