We have designed and built a pyroelectric optical detector for use as a transfer standard for the calibration of optical power meters. The pyroelectric element is made from lithium tantalate (LiTaO3). Gold black is used as the optical absorber in a multiple reflection wedge-shaped trap structure, with a 5-mm diameter input aperture and an f/4 field-of-view. The detector’s spatial responsivity varies less than 1%. The responsivity as a function of wavelength varies less than 1% over a range from 0.45–1.55 µm and less than 4% from 1.55–10.6 µm. The measured noise equivalent power (NEP) is 5 × 10−8 W/Hz1/2. For this wavelength range and detector area, the measured NEP and spatial uniformity represents a significant improvement over comparable predecessors.
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