Characterization of Cd_1-xMn_xTe crystals grown by the Bridgman method and the zone melt method

Cd_1-xMn_xTe crystals have been grown by a Bridgman method (BM) and by a zone melt method (ZM). While the BM-grown crystals have a heavy twin (A.E. Turner, R. Gunshor and S. Datta, Appl. Opt. 22 (1983) 3152.) the ZM-grown crystals have twin-free and a heavy striation in the growth direction (R. Triboulet, A. Heurtel and J. Rioux, J. Crystal Growth 101 (1990) 131.). These defects affect a extinction ratio as a function of crystal plane. Both crystals grown by two methods have the insertion loss of 0.3 dB at 0.66 μm, the extinction ratio of more than 30 dB in these (1 1 1) crystal planes at 0.66 μm and these crystals have a large size (20 mm diameter × 40 mm length). While the distribution of the Faraday rotated angle × 30 mm length of the BM-grown crystal is 45 ± 3.5°, that of the ZM-grown crystal is 45 ± 0.3°. The uniformity of the Faraday rotated angle of the ZM-grown crystal is more stable than that of the BM-grown crystal. We have demonstrated crystal growth by the zone melt method (ZM) with the aim of the commercial production of a 45° Faraday rotator with a low cost and a high performance.