Characterization of a Noncolinear Acousto-Optic Tunable Filter and its Resolution Enhancement as a Near-Infrared Spectrometer

Abstract

An automatic near-infrared (NIR) spectrometer based on a noncolinear acousto-optic tunable filter (AOTF) is constructed for high-speed spectrometry. Its initial spectral characteristics are studied systematically for application. The AOTF is a solid-state, rugged, compact, and high-speed device and can be readily used for spectral measurement applications, but some broadening and overlapping effects will occur when it is used for the measurement of a narrow-band spectrum. In order to correct the spectral distortion and obtain a fine spectrum, a new resolution enhancement procedure, which combines conventional Fourier self-deconvolution (FSD) with our optimized evaluation function and objective parameters determination, is used to resolve the band-broadened and band-overlapped spectral lines. The self-deconvolved spectrum is in good agreement with the fine spectrum measured by a high-resolution grating spectrometer. This is, to our knowledge, the first resolution enhancement of an AOTF spectrum by analytical and numerical operation.