<title>First measuring results concerning a new thin-film absolute radiometer</title>

Abstract

In using silicon integrated-circuit technology now, we have developed a new detector for the absolute measurement of radiation fluxes by combining a thin-film thermopile with a (meandered) heating element arranged within the receiving area systen following our former thin-film absolute radiometer conception from 1980 . The sensing junctions and legs of the thermopile and the heater are supported on a thin Si.N4/SiO membrane formed by anisotropic etching of the Si base material. The multijunction thin-film thermopile is fabricated from BiSb and Sb in a muitilayer technique by microlithographic methods. The 76 sensing junctions are arranged on the periphere of the receivi area 7 mm in diyneter. The membrane and chip dimensions are 8 x 8 mm and 12.5 x 12.5 mm , resp. It is intended to minimize both the temperature coefficient (TC) of the responsivity and of the calibration of the device. First measuring results of responsivity of the detector, its TC, linearity, time constant and the local distribution of responsivity are represented and possibilities are shown to improve these parameters by choosing appropriate materials for the heater as well as the thermopile.

Mid-infrared absolute spectral responsivity scale based on an absolute cryogenic radiometer and an optical parametric oscillator laser

“…We use thin-film thermopile detectors (TS-76, IPHT-Jena) [19] as transfer standard detectors in our specific spectral region. The TS-76 thermopile sensor is made from 76 thinfilm thermocouples and coated with a thermally equalizing Ag layer, which has an absorbance of more than 90%.…”