LOW-COST ALGAAS LASER ARRAYS FOR SOLID STATE LASER PUMPS

SOLID STATE LASERS SUCH AS ND:YAG ARE BEING USED AS INTENSE SOURCES OF OPTICAL RADIATION FOR COMMERCIAL AND MILITARY APPLICATIONS. NASA'S INTEREST IN SUCH LASERS IS FOR USE ON A POLAR ORBITING SPACE PLATFORM TO PERFORM CRITICAL EXPERIMENTS TO MEASURE ATMOSPHERIC AEROSOLS AND MOLECULAR SPECIES. CONVENTIONALLY PUMPED WITH FLASHLAMPS, THESE LASERS HAVE LOW POWER CONVERSION EFFICIENCY AND SHORT LIFETIMES. BY USING ALGAAS DIODE LASER ARRAYS AS OPTICAL ND:YAG LASER PUMPS, HIGH POWER CONVERSION EFFICIENCIES AND IMPROVED RELIABILITY VALUES ARE POSSIBLE. THE PROPOSED PROGRAM OFFERS TWO INNOVATIVE CONCEPTS, BOTH BASED ON SPIRE'S ESTABLISHED GAAS/ALGAAS CONCENTRATOR SOLAR CELL TECHNOLOGY. THE FIRST CONCEPT IS BASED ON THE USE OF MOCVD TO GROW HIGHLY UNIFORM, LARGE AREA WAFERS FOR USE IN FABRICATING LOW COST DIODE LASER ARRAYS. THE COST AND YIELDS OF MOCVD MATERIAL ARE SIGNIFICANTLY MORE FAVORABLE THAN THOSE OF LPE GROWN MATERIAL. THE SECOND CONCEPT INVOLVES THE APPLICATION OF SPIRE-DEVELOPED GAAS CONCENTRATOR CELL TECHNOLOGIES TO DIODE LASER ARRAYS. SEMICONDUCTOR WAFER AND THERMAL PACKAGING COST CONSIDERATIONS ARE THE PRIMARY DRIVING FORCES WHICH LEAD TO THE PRESENT HIGH COSTS OF DIODE LASER ARRAYS. USE OF THE MOCVD ALGAAS SOLAR CELL TECHNOLOGY IS EXPECTED TO LEAD TO SIGNIFICANT COST REDUCTIONS.