Multi-mode heterodyne laser interferometry realized via software defined radio.

Area of Science:

• Optics and Photonics
• Spectroscopy
• Laser Physics

Background:

• Multi-mode optical frequency generation and processing enable advanced experiments in optomechanics, optical information processing, and multi-mode spectroscopy.
• Spectral-hole burning (SHB) spectroscopy faces challenges from shot noise due to laser power limitations.
• Existing techniques lack efficient methods for noise reduction in low-power spectroscopic environments.

Purpose of the Study:

• To develop a multi-mode heterodyne laser interferometric scheme for improved noise performance in spectroscopy.
• To demonstrate the production, detection, and separation of multiple optical frequency modes for enhanced sensing.
• To enable real-time phase noise subtraction and shot noise reduction in low-optical-power interferometry.

Main Methods:

• Utilized a software-defined radio platform for agile multi-mode laser signal generation and real-time data processing.
• Implemented an entirely open-source development environment for the interferometric scheme.
• Employed multi-mode averaging to reduce shot noise and phase noise in optical measurements.

Main Results:

• Successfully produced, detected, and separated multiple optical frequency modes.
• Achieved improved noise performance in low-optical-power interferometry through multi-mode techniques.
• Demonstrated the benefit of optical environment sensing for real-time noise subtraction.

Conclusions:

• The developed multi-mode interferometric scheme significantly enhances noise performance in low-power optical measurements.
• This technique offers a viable solution for laser stabilization in spectral-hole burning spectroscopy.
• The open-source, adaptable methods have broad applicability in various optical sensing and interferometry contexts.