We have experimentally demonstrated and report on the results of crystal growth, fabrication, design, development, and performance for the long-wavelength infrared (LWIR) hyperspectral imager based on an acousto-optic tunable filter (AOTF) utilizing an efficient crystal, thallium arsenic selenide (Ti3AsSe3 TAS). Results on the growth of 40-mm-diameter, 15-cm-long crystal boules, to fabricate 4.0-cm-long AOTF devices, and on the system design and performance are presented. To achieve an 8-cm-1-resolution AOTF, we developed a design utilizing growth at 10.6 deg off from the c axis of the crystal and achieved >37% efficiency. 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 a blackbody radiative source (hot filament), and represents the first time AOTF imaging has been achieved with a microbolometer camera. The filament was placed ≈25 cm in front of the AOTF, and the camera was aligned to the first-order diffracted beam of the AOTF. The AOTF was tuned to 10.6-μm wavelength by applying a 13.9-MHz rf signal to the transducer. Preliminary experimental results obtained for SF6 gas utilizing this system are reported.