All-mirror wavefront division interferometer for Fourier transform spectrometry across multiple spectral ranges

Area of Science:

• Optics and Photonics
• Spectroscopy
• Interferometry

Background:

• Standard Fourier transform spectrometers have limitations in certain laser-based applications.
• Developing versatile spectroscopic tools for wide spectral ranges is crucial for material science and chemical analysis.

Purpose of the Study:

• To design and demonstrate an all-mirror wavefront-division interferometer for multi-spectral range spectroscopic studies.
• To present a theoretical framework and validate it with simulations and experiments.
• To showcase its capability for measuring sample dispersion.

Main Methods:

• Utilized an all-mirror wavefront-division interferometer design.
• Developed a theoretical framework with an analytical solution for far-field interference patterns.
• Employed cost-effective off-the-shelf components, including knife-edge prisms.
• Validated the design through optical propagation simulations and experimental results.
• Coupled the system with an octave-spanning supercontinuum source (1.5 µm - 4.4 µm).

Main Results:

• Demonstrated an ultra-broad optical bandwidth, high throughput, and dispersion-free operation.
• Achieved variable arm split ratio and a simple architecture.
• Successfully performed transmission spectroscopy on polymers (polypropylene) and gas (methane).
• Successfully performed reflectance spectroscopy on pharmaceuticals (insulin products).

Conclusions:

• The developed interferometer is a viable and prospective alternative to standard Fourier transform spectrometers for laser-based applications.
• The system's design inherently allows for the measurement of sample dispersion.
• The practical implementation with affordable components proves its feasibility for diverse spectroscopic studies.