n-GaAs thermo-voltage detector for short and powerful CO/sub 2/ laser pulses

Conceiving detectors, which can monitor the spatial and temporal beam distribution of (sub)-ns and powerful (> 1 MWcm/sup -2/) CO/sub 2/ laser pulses without optical attenuation and electrical amplification is a challenging issue. We present theoretical and experimental results of our novel detector based on optically induced electron temperature gradients in resonant plasmas in n-GaAs. We measured a responsivity up to 8 mV/MWcm/sup -2/ at optical power levels in the range from 1 to 100 MWcm/sup -2/ where other detectors strongly degrade or even fail.