SOLID-STATE MULTIPLE-PASS AMPLIFIER FOR DIODE PUMPED COHERENT LASER RADAR SYSTEMS

SOLID-STATE LASER SYSTEMS HAVE BEEN IDENTIFIED AS A PARTICULARLY EFFECTIVE TRANSMITTER TECHNOLOGY FOR USE IN COHERENT LASER RADAR SYSTEMS, DUE TO THEIR NEAR-IR WAVELENGTH (1-2UM), COMPACTNESS, FREQUENCY AGILITY, AND EFFICIENCY. RECENT ADVANCES IN LASER DIODE ARRAY TECHNOLOGYHAVE OPENED NEW PROSPECTS FOR LONG LIFE, HIGH ENERGY AND AVERAGE POWER SOLID-STATE LASER RADAR INSTRUMENTS SUITABLE FOR EXTENDED, UNATTENDED USE IN SPACE. IN THIS STUDY, THE ND:YAG MASTER OSCILLATOR, POWER AMPLIFIER (MOPA) LASER RADARCONFIGURATION HAS BEEN SELECTED AS THE "BEST FORM" SYSTEM FOR STRATEGIC APPLICATIONS. FEASIBILITY OF A MOPA MULTIPLE-PASS SLAB AMPLIFIER WITH THE REQUIRED SPECIFICATIONS IS BEING INVESTIGATED: DIFFRACTION-LIMITED OPTICAL PERFORMANCE, EFFICIENT DIODE-ARRAY PUMPED OPERATION,AND HIGH AVERAGE POWER CAPABILITY. THE STEPS TO ACHIEVING THIS GOAL FIRST INVOLVE THE SPECIFICATION AND PROCUREMENT OFA HIGH PERFORMANCE MINIATURE ND:YAG AMPLIFIER SLAB CAPABLE OF VERY LOW DISTORTION OPERATION. ONCE FABRICATED, THE HIGHPERFORMANCE SLAB WILL BE FULLY CHARACTERIZED IN AN EXISTING FLASHLAMP-PUMPED MULTIPLE-PASS AMPLIFIER TEST FIXTURE TO PROVIDE DATA NECESSARY FOR THE OPTIMIZATION OF AN ALL-SOLID-STATE SLAB AMPLIFIER. DESIGN AND DEVELOPMENT OF THE DIODE-PUMPED VERSION IS BEING INITIATED WITH A GOAL OF PROVIDING A SOLID FOUNDATION FOR THE FULLY DIODE-PUMPED AMPLIFIER DEVELOPMENT IN LATER RESEARCH. THE DEVELOPMENT OFAN ALL-SOLID-STATE COHERENT LASER RADAR SYSTEM IS A VITAL LINK IN THE CHAIN OF TECHNOLOGIES REQUIRED FOR STRATEGIC DEFENSE AND TARGET RECOGNITION APPLICATIONS. A MULTIPLE-PASS, VERY HIGH GAIN SLAB AMPLIFIER HAVING DIFFRACTION-LIMITED PERFORMANCE MUST BE DEVELOPED TO ACHIEVETHIS GOAL IN THE NEAR TERM. COMMERCIAL AND RESEARCH APPLICATIONS FOR A HIGH PERFORMANCE SLAB AMPLIFIER INCLUDE SPECTROSCOPY, COMMUNICATIONS, AND METEDOROLOGICAL RESEARCH. TECHNOLOGY DEVELOPED IN THIS EFFORT WOULD ALSO BE APPLICABLETO EYESAFE AND BROADLY TUNABLE SOLID-STATE MATERIALS.