SYSTEMS

WE PROPOSE TO DEVELOP A TECHNIQUE FOR RAPID TEMPORAL AND SPATIAL IMAGING OF HIGH POWER LASER BEAMS. THIS METHOD IS WINDOWLESS AND MAY BE EMPLOYED WHERE LASER INTENSITIES EXCEED THE DAMAGE THRESHOLDS FOR CONVENTIONAL CALORIMETRIC METHODS. THE DIAGNOSTIC UTILIZES THE TECHNIQUE OF OPTICAL-INFRARED DOUBLE RESONANCE TO OBSERVE BEAM INTENSITIES. IN THIS TECHNIQUE, THE OUTPUT OF A MWIR CHEMICAL LASER (DF) IS COMBINED WITH THE OUTPUT OF A VISIBLE/UV PROBE LASER TO PRODUCE OR MODULATE THE FLUORESCENCE OF A SIMPLE DIATOMIC MOLECULE SEEDED IN A GAS FLOW THROUGH WHICH THE LASER PROPAGATES. THE INTENSITY OF THE FLUORESCENCE IS LINEARLY PROPORTIONAL TO EACH OF THE LASER INTENSITIES. THE OVERLAP OF THE IR AND PROBE BEAMS DEFINES A CROSS SECTION OF THE IR BEAM, WHICH IS IMAGED ON TO A TWO-DIMENSIONAL INTENSIFIED ARRAY WITH 1 PERCENT SPATIAL RESOLUTION. TEMPORAL RESOLUTION IS DETERMINED BY THE LENGTH OF THE PROBE LASER PULSE (15 NS).AN ATMOSPHERIC PRESSURE LAMINAR FLOW JET WILL SEED THE MOLECULE TO BE EXCITED INTO THE GAS STREAM. PHASE I RESEARCH WILL SELECT FROM MANY POSSIBLE IMAGING MOLECULES AND PERFORM EXCITATION AND QUENCHING MEASUREMENTS TO DETERMINE OPTIMUM CANDIDATES. A RAMAN-SHIFTED PULSED DYE LASER WILL BE USED TO SIMULATE THE PEAK POWER OUTPUT OF A CW DF CHEMICAL LASER. A SECOND DYE LASER WILL BE USED AS THE PROBE LASER. POSSIBLE CANDIDATE MOLECULES INCLUDES THE HALOGENS, INTERHALOGENS, AND NITRIC OXIDE.