Interferometric autocollimator based on full-field heterodyne phase-shifting interferometry.

Area of Science:

• Optical Engineering
• Metrology
• Precision Measurement

Background:

• Accurate small-angle measurement is crucial in various scientific and industrial applications.
• Existing autocollimator designs can be complex and limited in resolution.

Purpose of the Study:

• To develop a compact and high-precision interferometric autocollimator.
• To leverage full-field heterodyne phase-shifting interferometry (HPSI) for enhanced angular measurement accuracy.

Main Methods:

• An oblique fiber and autocollimating objective lens form the core autocollimation module.
• The oblique fiber acts as a light source, beam splitter, and position sensor for system self-consistency.
• Heterodyne phase-shifting interferometry (HPSI) is employed to analyze wavefront differences for angle determination.

Main Results:

• The proposed system achieves high-precision small-angle measurement capabilities.
• A fiber-coupling efficiency model was developed to assess system errors.
• Experimental validation confirmed the system's feasibility and high-resolution performance.

Conclusions:

• The novel interferometric autocollimator offers a compact and self-consistent architecture.
• The integration of HPSI enables accurate angular deviation retrieval.
• The developed system demonstrates significant potential for precision metrology applications.