QCL-based nonlinear sensing of independent targets dynamics

Area of Science:

• Quantum optics and laser physics.
• Nonlinear optics and spectroscopy.
• Interferometry and optical sensing.

Background:

• Quantum-cascade lasers (QCLs) exhibit unique nonlinear optical properties.
• Stable interferometers are crucial for precise displacement measurements.
• Measuring independent displacements of multiple targets presents a significant challenge.

Purpose of the Study:

• To demonstrate a novel common-path interferometer for measuring independent displacements of multiple targets.
• To utilize the nonlinear frequency mixing properties of QCLs for enhanced sensing.
• To validate the experimental setup with numerical simulations.

Main Methods:

• Implementation of a common-path interferometer design.
• Exploitation of nonlinear frequency mixing in a quantum-cascade laser (QCL).
• Application of strong optical feedback to stabilize the QCL and access its nonlinearity.
• Utilizing an external dual-cavity setup for target interaction.
• Comparison of experimental results with Lang-Kobayashi equation-based numerical simulations.

Main Results:

• Successful measurement of independent displacements of multiple targets.
• Demonstration of the QCL's intrinsic nonlinearity being accessed via optical feedback.
• Experimental data showed excellent agreement with numerical simulations.
• The common-path design ensured high stability for the sensing system.

Conclusions:

• The developed QCL-based interferometer offers a robust method for multi-target displacement sensing.
• Nonlinear frequency mixing in QCLs provides a powerful tool for optical sensing applications.
• The study validates the theoretical models and experimental approach for advanced interferometry.