Low-light-level imaging in the visible and infrared

Summary form only given. Infrared focal plane array designers migrated from CCD readouts to CMOS multiplexer technology in the mid- to late-1980's. This paradigm shift was spurred by compelling needs for robust pixel-based amplifiers, reduced sensor development cost and higher on-chip integration. Though many available low-light-level cameras still exploit CCD sensor technology for signal readout, deep submicron CMOS technology is now facilitating a similar migration for visible and near-infrared sensors. In addition, CMOS-based imagers can offer lower temporal noise at video rates and practical advantages with respect to on-chip integration of camera-related functions. While modern CCD noise is dominated either by output amplifier thermal noise (after the application of correlated double sampling in off-chip support circuits) or extraneous system noise due to insufficient signal gain, the alternative CMOS paradigm provides lower temporal noise because the noise bandwidth is orders of magnitude smaller. This advantage is leading to the development of hybrids that utilize either silicon p-i-n detectors or alternative materials with wider bandgap to reduce dark current and raise operating temperature.