COMPACT, LIGHTWEIGHT EXPANDING BEAM CO2 LASER AMPLIFIERS FOR SPACEDBASED APPLICATIONS

THE EXPANDING BEAM LASER (EBL) CONCEPT IS A REVOLUTIONARY METHOD FOR FABRICATING EFFICIENT, LIGHTWEIGHT, COMPACT CO2 LASERS FOR SPACEBASED LASER RADAR APPLICATIONS. THE MAIN ADVANTAGE OF THIS CONCEPT IS THAT IT ENABLES THE CONSTRUCTION OF LASER POWER AMPLIFIERS HAVING STAGE GAINS THAT ARE FACTORS OF 10-30 GREATER THAN WITH CONVENTIONAL APPROACHES. IN THE CASE OF THE CO2 LASER, EFFICIENT POWER AMPLIFIERS WITH GAINS OF 1000 CAN BE BUILT WITH NO ISOLATIONAND WITH NEGLIGIBLE LOSSES FROM AMPLIFIED SPONTANEOUS EMISSION. AS A RESULT THE OSCILLATOR THAT PROVIDES THE INJECTED SIGNAL FOR A MASTER OSCILLATOR - POWER AMPLIFIER (MOPA) CAN BE REDUCED IN ENERGY BY A FACTOR OF 10-30 THEREBY REDUCING THE OVERALL LASER WEIGHT AND VOLUME BY A FACTOR OF NEARLY 2. TWO TECHNICAL OBJECTIVES WILL BE COMPLETED DURING PHASE I. (A) DETAILED ENGINEERING DESIGN OF A CO2 LASER MOPA USING THE EBL ARCHITECTURE. (B) VERIFICATION THAT THE EBL AMPLIFIER RESULTS IN THE LIGHTEST,MOST COMPACT LASER RADAR SYSTEM THROUGH EXTENSIVE LASER MODELLING AND BY ESTIMATING THE SIZE AND WEIGHT OF THE COMPONENTS OF THE LASER SYSTEM FOR BOTH THE EBL AND CONVENTIONAL LASER ARCHITECTURES. USING THESE CONCEPTUAL DESIGNS, A PROOF-OF-PRINCIPLE EXPERIMENT WILL ALSO BE DESIGNED IN PHASE I.