Short-wave infrared (SW-IR) radiometers have been developed to extend the NIST reference responsivity
scales from the silicon wavelength range to 2500 nm. In addition to spectral power responsivity measurements,
where 5 mm diameter extended-InGaAs (EIGA) detectors are underfilled by the incident radiation, irradiance
responsivity calibrations are needed. Irradiance measuring radiometers are used as reference detectors to
calibrate field radiometers in both irradiance and radiance measurement modes. In irradiance mode, smaller
detectors with high shunt resistance, such as 1 mm diameter short-wave HgCdTe and EIGA detectors are used.
Mechanical, optical, thermal, and electronic design considerations of SW-IR radiometers are discussed. Noise
equivalent currents (NEC) were measured to evaluate noise equivalent power (NEP) and D*.
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