A new class of position-sensitive detectors has been developed at Los Alamos Scientific Laboratory (LASL). These detectors utilize Seebeck effect and thermal diffusion in the detector material (Si). Large area (up to 125 cm2) detectors with only four electrodes yield accurate x-y position sensing for cw and pulsed laser beams. The detectors are sensitive to any laser wavelength and feature high optical damage thresholds (>109 W/cm2 at 10 μm). The detector responses are found to agree accurately with a thermal diffusion model that has no adjustable parameters. These detectors are currently in use on Helios and are planned for use on Antares, the LASL laser fusion systems.
R. B. Hammond, R. B. Hammond,
"New Position-Sensitive Detector For Pulsed Or CW Laser Beam Alignment", Proc. SPIE 0190, Los Alamos Conference on Optics 1979, (13 November 1980); doi: 10.1117/12.957769; https://doi.org/10.1117/12.957769