Performance benefits of charge-domain gain in active shortwave infrared targeting

The sensitivity of active targeting systems in the shortwave infrared band is currently limited by high read noise associated with conventional readout integrated circuitry. This limit imposes a barrier to leveraging other performance trades, such as source power, illumination wavelength, and temporal coherence. Introducing gain in the charge domain prior to signal readout can reduce the impact of read noise, to the point that it no longer limits performance. In preparation for a series of planned active-imaging field tests, we demonstrate improved system performance on a modeling basis with two different charge-domain gain cameras: the electron bombarded active pixel sensor (EBAPS) and the mercury cadmium telluride avalanche photodiode sensor. We find that both solutions mitigate read noise to make either one suitable for laser range gating, but the high dark current associated with EBAPS may make it unsuitable for continuous-wave imaging in some scenarios. These results aid in our understanding of expected performance in field testing of charge-domain gain systems.