BROADBAND PLASMA BARRIERS FOR HARDENING OPTICAL SENSORS IN THE 8-12 MICRON REGION

ANTROPIX CORPORATION PROPOSES TO OBTAIN TIME - RESOLVE OPTICAL PROPERTIES MEASUREMENTS (PLASMA OPACITY IN THE 8 - 12 MICRON SPECTRAL REGION, AS WELL AS STARK BROADENING AND RELATIVE INTENSITY PARAMETERS) ON BROADBAND PLASMA BARRIERS (BPBS) GENERATED BY LASER ACTIVATION OF ALKALI METAL (E.G., NA AND CS) VAPORS. SIMILAR MEASUREMENTS WILL BE COMPLETED ON KNOWN PHASE TRANSITION MATERIALS (PTMS) SUCH AS VANADIUM OXIDE IN ORDER TO CALIBRATE THE EXPERIMENTAL APPARATUS. ALKALI METAL VAPOR BPBS ARE PREDICTED TO BE EFFICIENT NONLINEAR OPTICAL SWITCHES THAT CAN BE ACTIVATED RAPIDLY (ON A NANOSECOND TIMESCALE) AT VERY LOW IRRADIANCE LEVELS, AFFORDING POTENTIALLY EXCEPTIONAL HARDENING FOR OPTICAL SENSORS EXPOSED TO LASER THREATS. PLASMA OPACITY, SPECTROSCOPIC DATA ON ELECTRON DENSITY AND TEMPERATURE, EMISSION SPECTRA (AND EMISSION INTENSITY WITHIN THE SENSOR BANDPASS), SWITCHING SPEED, DAMAGE THRESHOLDS, AND DURABILITY WILL BE MEASURED FOR ALKALI METAL VAPOR BPBS IN ORDER TO EVALUATE THE UTILITY OF THIS NEW NONLINEAR OPTICAL SWITCH FOR SENSOR HARDENING APPLICATIONS. IN PHASE I, EXPERIMENTS WILL EMPHASIZE PROTECTION OF 8 - 12 MICRON SENSORS, BUT IT IS ANTICIPATED THAT BROADBAND PLASMA BARRIERS WILL ALSO BE SUITABLE FOR PROTECTION OF SHORTER WAVELENGHT SENSORS.