High-Resolution, Laser-Heated High-Temperature Target Simulator

We describe a versatile 512 x 512 pixel high-temperature target simulator based on the use of radiation from laser diodes to heat small (~100 micron) graphite chip target elements. By using laser diodes in this manner we can avoid the need to make electrical contact with the target chips, thereby minimizing thermal conduction paths from each chip; by enclosing the target chips in a small vacuum enclosure (~5 cm in diameter) we eliminate convective heat losses and minimize the possibility of oxidization of the target chips. We further propose the use of optical fibers to link the laser diodes to the target chips; in this way we can separate the laser diode arrays from the high-temperature target array, greatly simplifying operation of the target simulator in a 20°K environment. Initial modeling suggests that at high temperatures the target elements can achieve thermal time constants on the order of 1 msec. Radiation by the target chips should very closely approximate blackbody radiation for wavelengths in the visible out to beyond 12 microns.