Phase closure retrieval in an infrared-to-visible upconversion interferometer for high resolution astronomical...

Area of Science:

• Astronomy and Astrophysics
• Optical Physics
• Signal Processing

Background:

• Observing faint infrared sources is challenging due to atmospheric interference and detector limitations.
• Interferometry is essential for high-resolution imaging, but phase information retrieval can be complex.
• Nonlinear optical processes offer novel ways to manipulate light signals for enhanced detection.

Purpose of the Study:

• To demonstrate a nonlinear upconversion technique for observing infrared sources using visible light detection.
• To experimentally validate the retrieval of phase information from infrared object spectra using a three-arm upconversion interferometer.
• To assess the efficacy of phase closure techniques with upconversion for astronomical imaging.

Main Methods:

• Utilizing a nonlinear upconversion process, specifically sum-frequency generation, to shift infrared signals to the visible domain.
• Employing a three-arm interferometer setup to capture interferometric signals.
• Conducting experiments with a laboratory binary star source to test phase information acquisition and preservation.

Main Results:

• Successful observation of an infrared source by detecting its upconverted interferometric signal in the visible spectrum.
• Experimental demonstration of retrieving phase information of the object spectrum using the upconversion interferometer.
• Real-time comparison confirming the preservation of essential phase information compared to standard interferometry.

Conclusions:

• Nonlinear upconversion is a viable method for observing infrared sources with visible light detectors.
• The developed upconversion interferometer effectively retrieves and preserves phase information necessary for image reconstruction.
• This technique holds promise for enhancing the capabilities of telescope arrays in astronomical observations.