Principle and analysis of the moving-optical-wedge interferometer

Area of Science:

• Optics and Photonics
• Interferometry
• Spectroscopy

Background:

• Traditional interferometers like the Michelson interferometer can be sensitive to mechanical disturbances and velocity variations.
• Low-spectral-resolution applications require instruments that can precisely control optical path differences (OPDs).

Purpose of the Study:

• To introduce and analyze a new type of interferometer: the moving-optical-wedge interferometer.
• To investigate the principle and properties of this novel interferometer design.
• To evaluate its applicability in low-spectral-resolution spectroscopy.

Main Methods:

• The interferometer design comprises a beam splitter, fixed mirrors, compensating plates, a fixed optical wedge, and a moving optical wedge.
• Optical path difference (OPD) is controlled by the linear displacement of the moving optical wedge.
• The relationship between physical displacement and OPD is modulated by the wedge angle and refractive index.

Main Results:

• A large physical shift of the moving optical wedge can result in a very small OPD value.
• The moving-optical-wedge interferometer demonstrates reduced sensitivity to velocity variations and mechanical disturbances compared to the Michelson interferometer.
• The instrument is effective for low-spectral-resolution applications across a broad wavenumber range.

Conclusions:

• The moving-optical-wedge interferometer presents a viable alternative for specific spectroscopic applications.
• Its design offers enhanced stability and precise OPD control, particularly beneficial for low-resolution spectroscopy.
• This interferometer is applicable from the far-infrared to the ultraviolet spectral regions.