Incoherent Fourier transform spectroscopy with room-temperature coverage from NIR to THz

TL;DR

This paper introduces a practical Fourier transform infrared spectrometer capable of broadband spectral coverage from NIR to THz at room temperature, enabling rapid, multi-band spectroscopy with a single optical setup.

Contribution

The authors develop a novel FTIR system using a diamond beam splitter and LTO detector, achieving simultaneous broadband coverage from 0.39 to 50 micrometers at room temperature.

Findings

Spectral coverage from 1 to 50 μm achieved in seconds.

Extendable to 90 μm and ultraviolet wavelengths.

Applicable to chemometry, material science, and medicine.

Abstract

Despite the broadband nature of thermal light sources, optical spectroscopy over multiple spectral bands simultaneously remains challenging. Here, we demonstrate a practical Fourier transform infrared spectrometer (FTIR) that achieves room-temperature spectral coverage from 1 to 50 $\mu$m (300--6 THz) in seconds using a single set of optics, with the long wave cutoff extendable to 90 $\mu$m (3.3 THz) and the short wave to the ultraviolet (0.39 $\mu$m). The interferometer employs a diamond plate beam splitter and windowless lithium tantalate (LTO) detector to probe the spectrum of combined incoherent sources operating at different temperatures. Applications of the instrument in modern chemometry, material science, and medicine are envisioned.