Laser heterodyne interferometer with rotational error compensation for precision displacement measurement

Area of Science:

• Optics and Photonics
• Metrology
• Precision Engineering

Background:

• Precision displacement measurement is crucial in various scientific and industrial applications.
• Rotational errors in the measured object can significantly degrade the accuracy of displacement measurements.
• Existing interferometric techniques often struggle to effectively compensate for these rotational errors.

Purpose of the Study:

• To propose and validate a laser heterodyne interferometer with integrated rotational error compensation.
• To enhance the accuracy and reliability of precision displacement measurements in the presence of angular deviations.
• To establish a robust mathematical model for displacement measurement incorporating rotational error compensation.

Main Methods:

• Development of a laser heterodyne interferometer incorporating an angle detecting unit.
• The angle detecting unit utilizes a semi-reflective film, polarizing beam splitter, quarter-wave plate, convex lens, and a 2D position sensitive detector.
• Design of the optical configuration and establishment of a mathematical model for compensation.

Main Results:

• Successful design and modeling of the interferometer with rotational error compensation.
• Detailed analysis of the coupling effect between axial displacement and rotational angle measurement.
• Experimental verification of the proposed interferometer's feasibility and performance.

Conclusions:

• The proposed laser heterodyne interferometer effectively compensates for rotational errors in precision displacement measurement.
• The integrated angle detecting unit provides accurate rotational error data for compensation.
• The developed system offers improved accuracy for displacement measurements where object rotation is a factor.