Fourier spectrometer based on digital micromirror device

Abstract

The invention discloses a Fourier spectrometer based on a digital micromirror device. The spectrometer comprises a light source, a slit, a collimating lens I, a band pass filter, a diffraction grating, a focusing lens, a digital micromirror DMD chip, a collimating lens II, a mixing and focusing optical device set, a sample cell, a detector, an I / V switching amplifier, an analog to digital converter, a microprocessor and a liquid crystal display. A system of the spectrometer temporally and spatially modulates the detecting light source by using a DMD chip based on frequency division multiplexing, and then detects a sample to obtain a modulated light detecting signal, and finally demodulates the detecting signal by using the digital Fourier transform technology to obtain the complete spectrum of the sample. Compared with the traditional Fourier spectrometer, the spectrometer adopts the DMD chip to replace precision mechanical moving assemblies like the Michelson interferometer, thereby greatly increasing the reliability, reducing the cost and the instrument size and achieving the purpose of portability. The spectrometer has low requirements for use environments, the detection processis fast and accurate, and the signal to noise ratio is high.

Description

technical field [0001] The invention relates to the technical field of spectrum analysis and detection, in particular to a Fourier spectrometer which utilizes a digital micromirror device to spatially modulate light. Background technique [0002] Spectrometers are highly versatile state-of-the-art measurement devices that can generally be classified into dispersive and interferometric spectrometers. Dispersive spectrometers usually use gratings as dispersive elements, however, in most applications, the measurement becomes challenging due to low light intensity, and thus has disadvantages such as low resolving power, small light energy output, narrow spectral range, and long measurement time . To overcome the SNR challenge, a common technique is to restore the amplitude of a measurement signal previously modulated at a different frequency with the aid of a lock-in amplifier. The operation of a lock-in amplifier relies on the orthogonality of the sinusoidal function. Techni...

AI Technical Summary

Problems solved by technology

Although it can provide high spectral resolution and high spectral coverage, it requires high-precision optical components and mechanical components as support, and the interferometer is expensive and mechanically unstable, which poses a challenge to the use environment of the spectrometer. high requirements

[0004] In summary, how to solve the problems of low signal-to-noise ratio, poor reliability, inconvenient portability, high requirements for the use environment and high cost of the spectrometer has become an urgent problem for those skilled in the art.

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