Analyses of infrared focal plane array figure of merit and its impact on sensor system trades

The performance of infrared focal plane arrays (IRFPAs) is usually described by a set of figures of merit and operating parameters. They include FPA format, pixel pitch, operating temperature, cut-on and cutoff wavelengths, median detectivity, uniformity, and integration time. This article examines the promise of superlattice infrared materials and how the improved FPA figure of merit affects sensor system performance as measured by range, update rate, size, power, and cost. A simple analysis shows that for space-based surveillance, the system cost, as measured by the number of hosting satellites, may be decreased substantially by using detector arrays with large array size and longer detection range. It also shows that to make long-wavelength superlattice IRFPAs useful for future space applications, the residual nonuniformity must be improved.