Channel dispersed Fourier transform spectrometer

Abstract

The high signal throughput of Fourier transform spectroscopy has proved a boon to overcoming the difficulties of otherwise overwhelming detector noise in chemical infrared spectroscopy and near-infrared Raman spectroscopy, and is desirable for in situ measurement. Here we introduce a stationary channel dispersed Fourier transform (CDFT) spectrometer that efficiently utilizes two-dimensional imagers to obtain high-resolution input spectra in low-pixel-density imagers. By angularly dispersing a vertical one-dimensional interference pattern along a horizontal axis, an array of bandlimited interferogram channels is measured with reduced sampling constraints in each channel. CDFT spectrometers can use existing imagers to measure spectra with 0.0025 cm−1 resolution over an 800 cm−1 bandwidth. Moreover, this approach reduces the quantization noise present in low dynamic range imagers significantly. To demonstrate the utility of CDFT spectroscopy, broadband spectral domain optical coherence and multicolor quantum dot photoluminescence are measured in low-pixel-density imagers.