Optical system design of a DMD-SHS combined modulation interference spectrometer

Area of Science:

• Spectroscopy
• Optical Engineering
• Interferometry

Background:

• Spatial Heterodyne Spectroscopy (SHS) offers advantages for spectral analysis.
• Conventional SHS systems have limitations in performance metrics like SNR and dynamic range.
• Secondary modulation techniques can potentially enhance SHS capabilities.

Purpose of the Study:

• To introduce and validate a novel Digital Micromirror Device (DMD) and Spatial Heterodyne Spectroscopy (SHS) combined modulation interference spectroscopy (DMD-SHS) system.
• To analyze the design requirements and modulation mechanism of the DMD-SHS.
• To demonstrate the practical feasibility and performance of the DMD-SHS for spectral detection.

Main Methods:

• Integration of a Digital Micromirror Device (DMD) for secondary modulation of interferometric data.
• Implementation of Hadamard transform for data processing.
• Design and construction of an experimental DMD-SHS device.
• Experimental validation using potassium spectra detection.

Main Results:

• The DMD-SHS system successfully achieved a spectral resolution of 0.0327 nm.
• The experimental setup covered a spectral range of 763.66–771.25 nm.
• Detection experiments using a potassium lamp and integrating sphere confirmed the system's capability.

Conclusions:

• The combined DMD-SHS modulation interference spectroscopy is a feasible technique.
• DMD-SHS significantly improves spectrometer performance, including SNR, dynamic range, and spectral bandwidth.
• The developed experimental device demonstrates effective spectral detection capabilities.