An Improved High-Gain Panel Light Amplifier

A grooved photoconductor light-amplifying picture panel is described, whose gain is more than 10 times greater than any previous amplifier and whose threshold for input light is reduced. These improvements have been obtained with a new electrode structure which enables a more efficient type of operation and by the use of a more sensitive photoconductive powder. Measured input-output characteristics are shown comparing the new and earlier types of operation and also indicating the effects of different supply frequencies. The time-integrated energy gain for a one-second excitation is of the order of 100 with input light of the same spectral distribution as the output. The asymptotic energy gain after a longer excitation interval is about 800 with optimum spectral matching of the photoconductor. Although the decay time is of the order of seconds, as with early amplifiers, the shape of the decay curves and the rate of decay are changed by the new method of operation.