Tunable transportable spectroradiometer based on an acousto-optical tunable filter: Development and optical performance

We describe a high-performance, transportable, versatile spectroradiometer based on an acousto-optical tunable filter (AOTF). The instrument was developed fortemperature metrology, namely, to determine the thermodynamictemperature of black bodies above the Ag freezing point (961.78  °C). Its main design feature is the attenuation of thediffraction side lobes (and, thus, out-of-band stray light) thanks to the use of a double-pass configuration. Theradiofrequency tuning of the AOTF allows continuous, fine, and rapid wavelength control over a widespectral range (650 nm –1000 nm). The instrument tunability can be easily calibrated with an Arspectral lamp with reproducibility within 10 pm over one week. The instrument was characterised in terms of relative signal stability (few 10−4) and wavelength stability (1 pm) over several hours. Thespectral responsivity of the instrument was calibrated with two complementary methods: tuning of the wavelength of the optical source or tuning theradiofrequency of the AOTF. Besides the application for thermodynamictemperature determination at the lowest uncertainty level, this instrument can also be used for multispectral non-contact thermometry of processed materials of non-grey and non-unitary emissivity (in the glass or metallurgical industries).

Source: Review of Scientific Instruments - December 2, 2016 Category: Physics Authors: O. Kozlova, A. Sadouni, D. Truong, S. Briaudeau and M. Himbert Source Type: research