Spectral instruments based on acousto-optical tunable filters: advantages and prospects

Abstract

Acoustics 08 Paris 1475Brief review of modern spectral techniques and instruments based on acousto-optical tunable filters (AOTF) is presented. New approaches for spectrometers and spectral systems development are considered. There are presented and described a series of compact spectrometers and spectrophotometers of ultra-violet, visible, and infra-red ranges for Raman, fluorescence, and absorption spectroscopy for various applications, including out-ofdoor measurements, spectroradiometers for environment monitoring (open air, Earth surface, and depth seawater), specialised spectral equipment for industrial monitoring (microelectronics, alcoholometry), imaging spectral devices, and instruments for differential spectroscopy. Also some fundamental problems of AOTF-based spectroscopy are considered: spectrogram correction of instrument function distortions, spectral resolution of different methods, modulation techniques for instrument function synthesizing, optimization of measurement procedures, including adaptive algorithms. Basic trends of past 30 year's AOTF-based spectroscopy development are formulated. The most promising ideas are discussed.

Multi-object spectrometer with micromirror array

“…The major disadvantages of the first approach are the connection between the spatial resolution and the spectral resolution (both are determined by the slit width), use of mechanical scanning systems, and the relatively long time period required for acquisition of hyperspectral images with sufficient spectral and spatial resolution [6][7][8][9][10][11][12]. In the second approach, when using a set of mechanically switched filters, the spectral resolution is usually low, and the use of tunable filters (optoacoustic, electro-optic, interference polarization) does not provide fast response and lets us work only with small aperture angles [13].…”

“…The major disadvantages of the first approach are the connection between the spatial resolution and the spectral resolution (both are determined by the slit width), use of mechanical scanning systems, and the relatively long time period required for acquisition of hyperspectral images with sufficient spectral and spatial resolution [6][7][8][9][10][11][12]. In the second approach, when using a set of mechanically switched filters, the spectral resolution is usually low, and the use of tunable filters (optoacoustic, electro-optic, interference polarization) does not provide fast response and lets us work only with small aperture angles [13].Development is underway for alternative approaches potentially promising gains in aperture and HSI acquisition time as a result of a multiplex approach and based on the principles of Fourier transform spectroscopy [14,15]. However, at this time the instrumentation cannot compete with traditional types of hyperspectrometers.…”