Space Qualification Studies of AOTF Devices Under the MISSE-11 Mission

The acousto-optic tunable filter (AOTF) devices are used in a variety of applications including hyperspectral and spectrapolarimetric based imaging. The AOTF devices provide several advantages including speed and random access to desired spectral bands and enable all-solid-state operation that are attractive for space applications. In this paper, the performance of Tellurium Dioxide (TeO2) and Mercurous Bromide (Hg2Br2) AOTF devices in space environment carried out under the NASA’s Materials International Space Station Experiments 11 (MISSE-11) mission is discussed. The purpose of the MISSE-11 mission was to study materials and devices subjected to space conditions for long term while attached to the International Space station (ISS). The TeO2 AOTF was developed for short wavelength IR (SWIR) operation while the Hg2Br2 AOTF device was developed for long wavelength IR (LWIR) operation. These devices were attached to the ISS platform for more than a year. Pre-flight and post-flight performance characterization were performed on these devices. In the case of TeO2 AOTF, the preflight efficiency was around 87% with a center frequency at 68MHz while the post-flight efficiency was around 83%. However, the optical transmission of Hg2Br2 AOTF had deteriorated considerably. The details of performance testing and analysis of both AOTF devices are discussed.