GROWTH OF ZINC GERMANIUM PHOSPHIDE FOR OPO APPLICATIONS

AN OPTICAL PARAMETRIC OSCILLATOR (OPO) CAN PROVIDE HIGH-POWER, INFRARED TUNABLE OVER A BROAD RANGE. THE DEVELOPMENT OF OPO DEVICES HAS BEEN LIMITED BY THE SCARCITY OF HIGH-QUALITY, NON-LINEAR CRYSTALS AND LOW LASER-DAMAGE THRESHOLD. ZNGEP2 SINGLE CRYSTALS HAVE AN EXCEPTIONALLY HIGH FIGURE OF MERIT (D(2)/N(3), WHERE D IS THE NON-LINEAR COEFFICIENT AND N IS THE INDEX OF REFRACTIONS THAT IS APPROXIMATELY FOUR TIMES THAT OF AGGASE2. A CRYSTAL GROWTH PROCESS FOR ZNGEP2 WILL BE DEVELOPED USING A HIGH-PRESSURE CZOCHRALSKI TECHNIQUE, RATHER THAN THE SEALED-CRUCIBLE, BRIDGMAN METHOD USED FOR AGGASE2. THIS PROCESS SHOULD PRODUCE HIGHER-QUALITY CRYSTALS WITH LOW ABSORPTION, HIGH UNIFORMITY AND GOOD OPTICAL QUALITY. THE PROJECT INCLUDES THE DEVELOPMENT OF SUPERPOLISHED SURFACES AND HIGH-DAMAGE-THRESHOLD AR COATINGS. SELECTED CRYSTALS WILL BE CHARACTERIZED WITH RESPECT TO WAVEFRONT DISTORTION, X-RAYROCKING CURVES SURFACE ROUGHNESS, ABSORPTION COEFFICIENT, AND SURFACE QUALITY. CHARACTERIZED CRYSTALS, POLISHED AND AR COATED, WILL BE DELIVERED TO NASA FOR EVALUATION AS IN OPO FOR THE SPECTRAL REGION OF 2.5 TO 5.5 MUM. AN OPTICAL PARAMETRIC OSCILLATOR (OPO) CAN PROVIDE HIGH-POWER, INFRARED TUNABLE OVER A BROAD RANGE. THE DEVELOPMENT OF OPO DEVICES HAS BEEN LIMITED BY THE SCARCITY OF HIGH-QUALITY, NON-LINEAR CRYSTALS AND LOW LASER-DAMAGE THRESHOLD. ZNGEP2 SINGLE CRYSTALS HAVE AN EXCEPTIONALLY HIGH FIGURE OF MERIT (D(2)/N(3), WHERE D IS THE NON-LINEAR COEFFICIENT AND N IS THE INDEX OF REFRACTIONS THAT IS APPROXIMATELY FOUR TIMES THAT OF AGGASE2. A CRYSTAL GROWTH PROCESS FOR ZNGEP2 WILL BE DEVELOPED USING A HIGH-PRESSURE CZOCHRALSKI TECHNIQUE, RATHER THAN THE SEALED-CRUCIBLE, BRIDGMAN METHOD USED FOR AGGASE2. THIS PROCESS SHOULD PRODUCE HIGHER-QUALITY CRYSTALS WITH LOW ABSORPTION, HIGH UNIFORMITY AND GOOD OPTICAL QUALITY. THE PROJECT INCLUDES THE DEVELOPMENT OF SUPERPOLISHED SURFACES AND HIGH-DAMAGE-THRESHOLD AR COATINGS. SELECTED CRYSTALS WILL BE CHARACTERIZED WITH RESPECT TO WAVEFRONT DISTORTION, X-RAYROCKING CURVES SURFACE ROUGHNESS, ABSORPTION COEFFICIENT, AND SURFACE QUALITY. CHARACTERIZED CRYSTALS, POLISHED AND AR COATED, WILL BE DELIVERED TO NASA FOR EVALUATION AS IN OPO FOR THE SPECTRAL REGION OF 2.5 TO 5.5 MUM.