FLASHLAMP PUMPED DYE LASER AMPLIFIER FOR NA LASER GUIDE STAR

THE USE OF LARGE GROUND BASED ADAPTIVE OPTICS TELESCOPES HOLDS THE POTENTIAL TO REVOLUTIONIZE ASTRONOMICAL OBSERVATION AT VISIBLE WAVELENGTHS. IN ORDER TO MAKE SUCH SYSTEMS PRACTICAL, BRIGHT SOURCES (GUIDE STARS) MUST BE AVAILABLE OVER ALL REGIONS OF THE SKY. SUCH STARS CAN BE ARTIFICIALLY PRODUCED BY LASER EXCITATION OF RESONANCE RADIATION IN THE MESOSPHERIC SODIUM LAYER. THIS PROPOSAL ADDRESSES THE DEVELOPMENT OF A SUITABLE LASER. ANALYSIS OF THE LASER NEEDS HAS IDENTIFIED THE REQUIRED LASER PARAMETERS: WAVELENGTH: 589 NM BANDWIDTH: 600 MHZ PULSE DURATION: 21 USEC PULSE ENERGY: 126 MJ BEAM QUALITY: 6 X DL PULSE REPETITION: 100 PPS A MASTER OSCILLATOR/POWER AMPLIFIER DESIGN IS PROPOSED. THE OSCILLATOR CAN BE A COMMERCIALLY AVAILABLE CW DYE LASER. THIS PROPOSAL ADDRESSES THE DEVELOPMENT OF THE POWERAMPLIFIER. THE PHASE I WORK PLAN IS TO BREADBOARD AND EVALUATE TWO CONFIGURATIONS OF A DYE LASER PUMPED DYE AMPLIFIER. THE DATA WILL INCLUDE GAIN, BEAM QUALITY, AND EFFICIENCY MEASUREMENTS AS FUNCTIONS OF INPUT POWER, PUMP LASER FLUENCE, DYE CONCENTRATION, AND SOLVENT COMPOSITION AT LOW REPETITION RATES. THE RESULTS WILL BE USED TO PREPARE A BASELINE DESIGN SCALED TO 100 PPS. PHASE II WILL BE DEDICATED TO THE CONSTRUCTION OF THE SCALED LASER AND THE DEMONSTRATION OF A USABLE GUIDE STAR.