Low-NEP pyroelectric detectors for calibration of UV and IR sources and detectors
George P. Eppeldauer, Vyacheslav B. Podobedov, Leonard M. Hanssen, Catherine C. Cooksey
Pyroelectric radiometers with spectrally constant response have been developed at NIST with the cooperation of a few detector manufacturers. The new devices have noise-equivalent-power (NEP) values less than 1 nW/Hz^1/2 sufficiently low for use at the output of regular monochromators. Their response flatness is an order of magnitude better than that of filtered Si detectors and can be used to realize simple and low-uncertainty responsivity scales for the UV and IR wavelength ranges. For the first time, the UV irradiance responsivity of a pyroelectric detector has been determined. Based on spectral reflectance measurements of the black coating of the pyroelectric detector, the relative spectral response was determined between 250 nm and 30000 nm. The relative response was then converted into spectral power and irradiance responsivities using absolute tie points from a silicon-trap-detector in the VIS range. In addition to the UV irradiance responsivity scale realization, the flat response between 1600 nm and 2600nm was utilized and a constant irradiance responsivity was realized and applied as a reference scale for the Spectral Irradiance and Radiance Responsivity Calibrations with Uniform Sources (SIRCUS) facility of NIST. The spectral power responsivity of the low-NEP pyroelectric detector is the internal standard of the NIST VIS-IR detector calibration facility for the 600 nm to 24000 nm wavelength range. The pyroelectric standard is used to calibrate other types of detectors for spectral responsivity using detector substitution. The flat- response interval of the pyroelectric standard, calibrated for irradiance responsivity, was also used to measure the integrated irradiance from UV LED sources without using any source standard. The broadband radiometric measurements can be applied to IR LEDs emitting low fluxes between 750 nm and 4300 nm. All pyroelectric detector based calibrations were performed with expanded uncertainties of about 2 % (k=2).
16th International Conference on Solid State Lighting and LED-based Illumination Systems
August 8-9, 2017
San Diego, CA
International Society for Optics and Photonics (SPIE) Optical Engineering and Applications