Two-dimensional displacement measurement by quasi-common-optical-path heterodyne grating interferometer

Area of Science:

• Optical Metrology
• Interferometry
• Precision Measurement

Background:

• Accurate two-dimensional displacement measurement is crucial for various scientific and industrial applications.
• Traditional interferometric methods can be sensitive to environmental disturbances, impacting stability and accuracy.
• The quasi-common-optical-path (QCOP) configuration offers a potential solution for enhanced stability in interferometry.

Purpose of the Study:

• To present a novel method for two-dimensional displacement measurement using a specific QCOP configuration.
• To design and evaluate two measurement configurations: single and differential detection.
• To demonstrate the system's ability to maintain high stability during measurement.

Main Methods:

• Development of a measurement system incorporating a heterodyne light source, two-dimensional holographic grating, half wave plates, and lock-in amplifiers.
• Implementation of a specific quasi-common-optical-path (QCOP) configuration.
• Design and comparison of single detection and differential detection measurement configurations.

Main Results:

• The differential detection configuration exhibits superior sensitivity, resolution, and reduced nonlinear phase error compared to single detection.
• Experimental validation confirms the QCOP interferometer's capability for accurate two-dimensional displacement measurement.
• The system demonstrates high stability, making it suitable for precise metrology tasks.

Conclusions:

• The proposed QCOP interferometer provides a stable and effective platform for two-dimensional displacement measurement.
• Differential detection significantly enhances measurement performance metrics.
• This technology holds promise for applications requiring high-precision, stable displacement sensing.