Extension of the NIST spectral responsivity scale to the infrared using improved-NEP pyroelectric detectors

Abstract

Routine NIST spectral responsivity calibrations are needed for the infrared range. Low-NEP pyroelectric radiometers have been developed for traditional monochromator applications to extend the responsivity scale to the infrared. After NEP tests, the best pyroelectric detectors were converted to transfer-standard radiometers. The relative spectral responsivities were determined from spectral reflectance measurements of the organic black detector coatings. The absolute tie points were measured against a domed pyroelectric radiometer standard and a sphere-input extended-InGaAs transfer-standard radiometer. The infrared spectral power responsivity scale has been extended for the 2 µm to 14 µm wavelength range. A single-grating monochromator has been adapted to the calibration facility and used to characterize and calibrate infrared detectors.

Very Black Infrared Detector from Vertically Aligned Carbon Nanotubes and Electric-Field Poling of Lithium Tantalate

“…The detector evaluation was accomplished by a combination of methods: (1) near-normal hemispherical reflectance with a Fourier Transform Infrared (FTIR) spectrometer from 1 to 14 μm; , (2) absolute spectral responsivity with a blackbody source and a continuously variable spectral filter from 2.2 to 14 μm; (3) absolute responsivity with a blackbody source and a single bandpass filter from 1.5 to 1.9 μm; (4) absolute responsivity at discrete laser wavelengths of 1.32 and 10.6 μm; and (5) relative spectral responsivity with a broadband source and monochromator from 0.4 to 2 μm. Methods (2) to (4) provide absolute values through direct comparisons of the VAMWCNT-coated detector to a calibrated transfer standard detector. , All five measurements provide a picture of the detector’s optical absorption efficiency from 400 nm to 14 μm. In every case, the detector evaluation employed a measurement apparatus and procedure that is established at NIST in the category of calibration service.…”

“…Methods (2) to (4) provide absolute values through direct comparisons of the VAMWCNT-coated detector to a calibrated transfer standard detector. 16,17 All five measurements provide a picture of the detector's optical absorption efficiency from 400 nm to 14 µm. In every case, the detector evaluation employed a measurement apparatus and procedure that is established at NIST in the category of calibration service.…”

Extension of the NIST spectral power-responsivity calibration service to 2500 nm

“…The basis of the extended spectral responsivity scale is from the calibration of the spectral power responsivities at discrete wavelengths using a sphere-input EIGA radiometer which is, in turn, calibrated using the electrical-substitution cryogenic radiometer at the Spectral Irradiance and Radiance Responsivity Calibrations using Uniform Sources (SIRCUS) facility [1,3]. The calibrations at these discrete wavelengths were interpolated to other wavelengths using the SCF [2] spectral power-responsivity scale to 1600 nm, and the spectral responsivity of the low-NEP pyroelectric transfer-standard radiometer [6]. Four working-standard EIGA radiometers (with 5 mm diameter detectors) were calibrated against the sphere-input EIGA transfer standard.…”

Mid-infrared spectral responsivity scale based on an absolute cryogenic radiometer and a tunable quantum cascade laser

“…Thermal detectors with nearly flat spectral absorptivity have been used as transfer standards to extend the SR scale from visible or near infrared to the MIR range [11][12][13][14][15]. The method requires the optical radiant power and then the SR at only one wavelength point in the nearly flat absorption spectrum to be calibrated.…”