A method is described for the measurement of the noise-equivalent spectral radiance (NESR) of Fourier transform infrared (FTIR) spectroradiometers at all wave numbers of a selected range. The method requires minimal detailed knowledge of the sensor and no support equipment beyond a blackbody source. The NESRs of the FTIR spectroradiometer are determined at every wave-number increment in the 700–1300 cm−1 range, for six resolutions, with a conventional blackbody source and ensembles of differential spectra. The NESRs are well behaved and consistent with the expected dependence on resolution; however, they depend on source temperature at the highest (1 cm−1) and lowest (32 cm−1) resolutions, with little or no statistical dependence at intermediate resolutions. Residual source drift is shown to be the likely cause of the dependence at 1 cm−1; the dependence on the source at 32 cm−1 resolution is shown to be most probably due to photon noise. At intermediate resolutions the sensor noise is dominant.
© 2004 Optical Society of America
(010.1120) Atmospheric and oceanic optics : Air pollution monitoring
(030.5630) Coherence and statistical optics : Radiometry
(280.1120) Remote sensing and sensors : Air pollution monitoring
(300.6340) Spectroscopy : Spectroscopy, infrared
Dennis F. Flanigan, Alan C. Samuels, and Avishai Ben-David, "Noise Assessment of a Fourier Transform Infrared Spectroradiometer Subject to the Stability of a Conventional Laboratory Blackbody Source," Appl. Opt. 43, 2767-2776 (2004)