DEVELOPMENT OF A COMPACT 2 UM COHERENT LASER RADAR VIBRATION SENSOR

REMOTE SENSING OF VIBRATIONS USING COHERENT LASER RADAR (CLR) HAS BEEN IDENTIFIED AS A MEANS OF IDENTIFYING REMOTE TARGETS BY ANALYSIS OF CHARACTERISTIC VIBRATION SPECTRA. CO2 LASER TECHNOLOGY HAS BEEN USED IN EFFORTS UP TO THE PRESENT. RECENT ADVANCES IN EYESAFE ( 1.4 UM) SOLID-STATE LASER AND LASER RADAR TECHNOLOGY POINT TO A MORE SENSITIVE, COMPACT, SHORTER WAVELENGTH ALTERNATIVE, HIGHLY COMPATIBLE WITH THE REQUIREMENTS OF A RUGGEDIZED REMOTE VIBRATION SENSOR. IN PARTICULAR, A TM,HO:YAG CLR HAS RECENTLY BEEN DEMONSTRATED BY RESEARCHERS AT COHERENT TECHNOLOGIES, INC. TO BE A VERY SENSITIVE, LONG-RANGE EYESAFE SYSTEM OPERATING AT 2.1 UM WAVELENGTH. OPERATION AT THIS WAVELENGTH WOULD RESULT IN A MINIMUM DETECTABLE VIBRATION AMPLITUDE OF ROUGHLY ONE-FIFTH THAT OF A COMPARABLE CO2 SYSTEM. RAPID ADVANCES IN DIODE-PUMPED 2 UM LASER TECHNOLOGY AT CTI AND ELSEWHERE STRONGLY SUGGEST THAT A HIGH POWER, CW SINGLE-FREQUENCY TM,HO:YAG TRANSMITTER IS FEASIBLE HAVING THE OUTPUT POWER AND FREQUENCY STABILITY REQUIRED FOR VIBRATION SENSING APPLICATIONS. THIS PHASE I EFFORT WILL DETERMINE THE PRELIMINARY DESIGN OF A 2 UM COHERENT VIBRATION SENSOR AND DEMONSTRATE A HIGH POWER (1-2W CW) DIODE-PUMPED TRANSMITTER PROTOTYPE. ANTICIPATED BENEFITS/POTENTIAL COMMERCIAL APPLICATIONS - NUMEROUS MILITARY AND COMMERCIAL APPLICATIONS EXIST FOR A COMPACT, EFFICIENT EYESAFE REMOTE VIBRATION SENSOR. MACHINE VIBRATION ANAYLSIS IN INDUSTRIAL ENVIRONMENTS WOULD DIRECTLY BENEFIT FROM THE PROPOSED INSTRUMENT. SIMILAR TRANSMITTERS EMPLOYING PULSED OPERATION WOULD FIND IMMEDIATE USE IN HELICOPTER WIRE AVOIDANCE, METEOROLOGICAL RESEARCH, ON-BOARD WIND SHEAR AVOIDANCE, POLUTION MONITORING, AND GROUND-BASED WIND SENSING SYSTEMS.