Ultraviolet-visible imaging acousto-optic tunable filters in KDP

There is a need to develop large-aperture acousto-optic tunable filters (AOTFs) in the UV region for applications in astronomy, environmental sciences, biology, etc. We have developed a high-quality noncollinear AOTF cell that uses a single crystal of KDP that has nearly a four times larger acousto-optic figure of merit, M2, than quartz. The linear and angular apertures of this cell are 1.5 cm x 1.5 cm and 1.2 degrees, respectively. The spectral range is 220-480 nm, with 160-cm(-1) spectral resolution and high transmission in the UV. We present an analysis of the design and describe the characterization results.