Self-mixing interferometry with mutual independent orthogonal polarized light

Area of Science:

• Optics and Photonics
• Metrology
• Interferometry

Background:

• Traditional interferometers often struggle with non-cooperative targets.
• Self-mixing interferometry offers a compact solution but requires robust signal processing.

Purpose of the Study:

• To develop a self-mixing interferometry system utilizing orthogonal polarized light for enhanced displacement measurement.
• To demonstrate the feasibility of measuring non-cooperative targets with high resolution.

Main Methods:

• Employing two mutually independent, orthogonally polarized beams as both measuring and reference light.
• Utilizing frequency shifting and polarization multiplexing technologies.
• Simultaneous phase variation measurement of orthogonal beams via heterodyne demodulation with a lock-in amplifier.

Main Results:

• Accurate displacement measurement of the target is achieved through the phase difference of orthogonal polarized light.
• Experimental results confirm the feasibility of the proposed self-mixing interferometry system.
• A short-term resolution better than 2 nm was achieved under typical room conditions.

Conclusions:

• The developed self-mixing interferometry system effectively measures displacement of non-cooperative targets.
• The use of orthogonal polarized light and advanced signal processing enhances measurement accuracy and resolution.
• This technique presents a viable alternative for precision metrology applications.