Prism interferometer for a compact Fourier-transform spectroscope

Area of Science:

• Optical Engineering
• Spectroscopy
• Interferometry

Background:

• Fourier-transform spectroscopy (FTS) is a powerful technique for spectral analysis.
• Developing field-portable spectrometers presents challenges in terms of size, complexity, and environmental sensitivity.
• Existing interferometer designs can be sensitive to ambient conditions and require precise, time-consuming alignment.

Purpose of the Study:

• To develop a novel prism-scanning interferometer as a foundational component for a field-use spectrometer.
• To overcome limitations of traditional FTS systems, particularly for portable applications.
• To simplify the construction and operation of interferometers for field deployment.

Main Methods:

• A prism-scanning interferometer was designed and constructed.
• The interferometer utilizes a sliding triangular prism with two mirror surfaces coupled to a fixed triangular-prism beam splitter.
• The design was tested to evaluate its operational characteristics and performance.

Main Results:

• The prototype prism-scanning interferometer demonstrated basic functionality.
• The design effectively eliminates the influence of ambient air on measurements.
• Alignment procedures were significantly simplified compared to conventional designs.
• The optical path difference was doubled, halving the required stage-moving distance.
• Measured spectral resolution and wavelength scale closely matched theoretical calculations.

Conclusions:

• The developed prism-scanning interferometer is a promising step towards practical field-use spectrometers.
• The simplified and robust design offers advantages for portable spectroscopic instrumentation.
• This approach addresses key challenges in deploying FTS technology outside of laboratory settings.