Spatial-detection effects in laser radar.

Determination of a relation for the detector-aperture size for spatially coherent detection when dependent scattering is present. This relation is applied to several realistic laser-radar situations. It is concluded that no distortion of laser-radar signal signatures due to spatial-detection effects should be expected for present typical operating conditions (i.e., mean wavelength of the source = 0.6943 micrometer, and the diameter of the receiving aperture is about 10 cm). With development of longer-wavelength laser radars, in order to monitor signal returns at pollutant-gas absorption lines concomitantly larger receiver apertures must be used or else widely varying signal signatures will result even though similar conditions prevail.