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Infrared Degenerate Four-wave Mixing with Upconversion Detection for Quantitative Gas Sensing
Published on: March 22, 2019
Laboratory demonstration of an infrared-to-visible up-conversion interferometer for spatial coherence analysis
S Brustlein1, L Del Rio, A Tonello
1XLIM Département Photonique, UMR CNRS 6172, 123 Avenue A. Thomas, Limoges Cedex, France.
Physical Review Letters
|June 4, 2008
Summary
This study shows how to measure infrared source spatial coherence using an up-conversion interferometer. This method successfully distinguishes between two infrared sources, mimicking a binary star system.
Area of Science:
- Optics and Photonics
- Quantum Optics
- Interferometry
Background:
- Spatial coherence is a fundamental property of light, crucial for applications like imaging and remote sensing.
- Traditional methods for measuring spatial coherence often require complex setups or are limited to specific wavelength ranges.
- Up-conversion techniques offer a way to shift light to shorter wavelengths, potentially enabling new measurement capabilities.
Purpose of the Study:
- To experimentally demonstrate the retrieval of spatial coherence for infrared sources.
- To utilize an up-conversion interferometer for measuring spatial coherence.
- To validate the method by resolving the separation of simulated binary infrared sources.
Main Methods:
- An up-conversion interferometer was constructed using Ti-diffused periodically poled lithium-niobate waveguides.
- Sum-frequency generation was employed in both interferometer arms to convert infrared light to the visible domain.
- Interference fringe contrast in the visible domain was analyzed to determine spatial coherence.
- Measurements were cross-validated with a simultaneous reference interferometer operating in the infrared.
Main Results:
- The up-conversion interferometer successfully retrieved the spatial coherence of the infrared source.
- The method allowed for the resolution of the spatial separation of two uncorrelated pointlike infrared sources.
- The experimental results were consistent with those obtained from the infrared reference interferometer, confirming the validity of the technique.
Conclusions:
- Up-conversion interferometry provides a viable method for measuring infrared spatial coherence.
- This technique offers a practical approach for characterizing infrared sources, with potential applications in astronomy and metrology.
- The ability to convert infrared to visible light simplifies detection and analysis for spatial coherence measurements.
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