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This paper describes the development of acousto-optic tunable filter (AOTF) devices that are fabricated using in-house grown, high-quality single crystals of mercurous bromide (Hg2Br2). The Hg2Br2 crystals were grown using physical vapor transport (PVT). The quality of the Hg2Br2 single crystals are determined using high-resolution x-ray diffraction (HRXRD). The full width at half maximum (FWHM) of the (220) reflection was found to be 0.029 degrees, which is a significant improvement in the growth of Hg2Br2 bulk single crystals. The diffraction efficiencies of the fabricated AOTF device in the long wavelength infrared (LWIR) found to be 26% which is the highest reported. The device was tested for point detection and for imaging capabilities in the LWIR range. The study shows promising results using Hg2Br2 in LWIR AOTF-based technologies. [ABSTRACT FROM AUTHOR]

Thermal expansions of single crystals of mercurous halides grown by the physical vapor transport method have been investigated. The unit cell lattice parameters were measured by using x-ray diffraction, whereas, the bulk thermal expansion was investigated using the dilatometer instrument as a function of temperature. It was found by both techniques that mercurous halides exhibit positive linear thermal expansion along the a-axis and negative linear thermal expansion along the c-axis. However, the volume expansion in both methods was found to be positive. The coefficient of thermal expansion along the a-axis was significantly larger than the one along the c-axis giving a net positive volume expansion. [ABSTRACT FROM AUTHOR]

Single crystals of mercurous halide were grown by physical vapor transport method (PVT). The orientation and the crystalline quality of the grown crystals were determined using high resolution x-ray diffraction (HRXRD) technique. The full width at half maximum (FWHM) of the grown mercurous bromide crystals was measured to be 0.13 degrees for (004) reflection, which is the best that has been achieved so far for PVT grown mercurous halide single crystals. The extended defects of the crystals were also analyzed using high resolution x-ray diffraction topography. Preliminary studies were carried out to evaluate the performance of the crystals on acousto-optic modulator (AOM) and gamma-ray detector applications. The results indicate the grown mercurous halide crystals are excellent materials for acousto-optic modulator device fabrication. The diffraction efficiencies of the fabricated AOM device with 1152 and 1523 nm wavelength lasers polarizing parallel to the acoustic wave were found to be 35% and 28%, respectively. The results also indicate the grown crystals are a promising material for gamma-ray detector application with a very high energy resolution of 1.86% FWHM. [ABSTRACT FROM AUTHOR]