Hg2Cl2 crystals for efficient birefringence etalon filters

We have experimentally demonstrated the physical vapor transport growth of 30 mm diameter and 8 cm long mercurous chloride crystals for birefringence etalon filters. The [1 1 0] oriented seeded crystals were grown in a two zo ne vertical transparent furnace by vapor phase transport method. Two 5 mm a nd 1.5 mm thick filters were fabricated and tested interferometrically and with a spectrometer. The filter exhibited the spectral modulation expected based on the filter thickness. The effect of temperature on filter performa nce was studied by measuring the filter operation at specific calibrated te mperatures. We observed a significant shift in filter wavelength at 25.8 de grees C and 29.8 degrees C. (C) 1999 Published by Elsevier Science B.V. All rights reserved.