Abstract: A technique for performing background suppression in photodiode detectors is disclosed. A first detector measures the light emitted by the source to be measured and the background light, while a second detector simultaneously measures the background light only. The value measured by the second detector is subtracted from the value measured by the first detector, and the difference represents the portion of the first detector's measured value which is attributable to the source to be measured.

Abstract: Pyroelectric detection apparatus including a pyroelectric detector operative to produce an electric output in response to pulsed incident radiation and a discharge circuit for discharging the electric output. The discharge is operative to impose an effective high impedance on the pyroelectric detector during at least a portion of the duration of each radiation pulse and to impose a low effective resistance during the intervals between the radiation pulses.

Abstract: Apparatus for determining the energy of single pulses of rapidly pulsing laser radiation including first radiation sensing apparatus for providing a first signal output in response to single pulses of a plurality of pulses of rapidly pulsing radiation; second radiation sensing apparatus for providing a second signal output in response to a plurality of pulses of rapidly pulsing radiation, the second signal output being an indication of the overall average incident optical power of the plurality of pulses; and signal processing apparatus, associated with the first and second radiation sensing apparatus, for receiving and processing the first and second signal outputs so as to determine an average pulse rate of the plurality of pulses and thereby also to provide an output indication of the energy of single pulses of the plurality of pulses of rapidly pulsing radiation.