DEVELOPMENT OF LASERS OPTIMIZED FOR PUMPING TI:A12O3 LASERS

A SINGLE-FREQUENCY, HIGH-ENERGY, TI:A12O3, LIDAR TRANSMITTER IS CURRENTLY UNDER DEVELOPMENT FOR NASA LANGLEY RESEARCH CENTER. THIS SYSTEM REQUIRES TWO DIFFERENT TYPES OF TI:A12O3 PUMP LASER. THE MASTER OSCILLATOR REQUIRES A CW (OR QUASI-CW) PUMP LASER WITH A NOMINAL OUTPUT OF 1-2 W. THE GAIN-SWITCHED, HIGH ENERGY OSCILLATOR REQUIRES A PULSED PUMP WITH A PER-PULSE ENERGY OF ABOUT 2 J TO PRODUCE A 1 J TI:A12O3 OUTPUT. THE GOAL OF THIS SBIR PROJECT IS TO DEVELOP PUMP LASERS THAT ARE OPTIMIZED FOR THESE REQUIREMENTS. AN IDEAL PUMP FOR PULSED TI:A12O3 OSCILLATORS WOULD HAVE A 200-500-NS PULSEWIDTH. OUR DESIGN FOR THE PULSED PUMP LASER ACHIEVES THIS PERFORMANCE GOAL THROUGH AN INNOVATIVE USE OF: A GRADED-REFLECTIVITY-MIRROR UNSTABLE RESONATOR, HIGH-GAIN ND:YLF LASER MATERIAL, A COMPACT FARA-DAY ISOLATOR, AND THE STABLE-RELAXATION-OSCILLATION LASER (SROL)CONCEPT. THE IDEAL PUMP FOR A SPACE-BASED TI:A12O3 MASTER OSCILLATOR IS A DIODE-LASER-PUMPED, CW, ND-LASER WITH EFFICIENT INTRACAVITY SECOND HARMONIC GENARATION (SHG). WITH INVENTIVE DESIGN APPROACHES, LONGITUDINALLY-PUMPED OSCILLATORS MAY BE ABLE TO PRODUCE>1 W OF LASER OUTPUT AT THE SECOND HARMONIC WAVELENGTH USING EXISTING DIODE LASERS. AN ADDITIONAL GOAL OF THE PHASE I EFFORT WILL BE TO DEVELOP A DESIGN FOR SUCH A DEVICE.