InSb検知器を用いた遠赤外分光

抄録

A new far infrared spectroscopic method using an InSb tunable detector-tuned by a magnetic field-is proposed. If a far infrared source, obeying the Rayleigh-Jeans relation, is used with a grating spectrometer, whose transmittance is independent of wavelength, the detector output produced by the spectrum of order m is proportional to m³ for a thermal detector, to m for an InSb non-tunable detector while it has a sharp peak at some fixed m for a tunable detector. This advantage of the tunable detector is illustrated by the measurement of absorption spectra of water vapor using various values of the magnetic field.
It is proposed to change the spectral region covered by the detector synchronously with the motion of the grating, thus eliminating low-frequency-pass filters.