Operational Characteristics of LWIR AOTF Based Multispectral Imager

摘要

Northrop Grumman has designed, developed and demonstrated acousto-optic tunable filter (AOTF) based hyperspectral imager to cover visible to long wavelength infrared (LWIR) spectral region. We have experimentally demonstrated and report the results of crystal growth, fabrication, design, development and performance for the long wavelength infrared (LWIR) acousto-optic tunable filter (AOTF)-based hyperspectral imager based on an efficient crystal thallium arsenic selenide. The results on the growth of 40 mm diameter and 15 cm long crystals, 4.0 cm long AOTF fabrication, and system design and performance are presented. A system concept was developed with high efficiency, resolution, and throughput utilizing this TAS AOTF. The test setup consisted of an LWIR camera (microbolometer), the AOTF, and SF_6. The object was placed ～20" in front of the AOTF. The camera was aligned to the first order diffracted beam of the AOTF. The AOTF was tuned to 10.6 um wavelength by applying a 13.9 MHz RF signal on the transducer. The results on the growth of crystals, AOTF fabrication, and systems design and performance are presented.