Heterodyne interferometer with two parallel-polarized input beams for high-resolution roll angle measurement

Area of Science:

• Optical Metrology
• Interferometry
• Precision Measurement

Background:

• Accurate roll measurement is critical in various industrial applications.
• Traditional heterodyne interferometric systems face limitations in resolution and sensitivity.

Purpose of the Study:

• To propose and validate an improved heterodyne interferometric system for enhanced roll measurement resolution.
• To develop a mathematical model for the proposed system using Jones' calculus.

Main Methods:

• Utilizing two acousto-optic modulators to generate beams with different frequencies and identical polarization.
• Incorporating a quarter-wave plate in each path to create a beat frequency upon beam combination.
• Establishing a mathematical model based on Jones' calculus for system analysis.

Main Results:

• The simultaneous appearance of sensitive areas for both beams effectively doubles the measurement resolution.
• Experimental validation demonstrated a gain coefficient of 229 within the 0.1° range.
• The achieved gain coefficient is twice that of traditional roll measurement methods.

Conclusions:

• The proposed heterodyne interferometric system offers significantly enhanced resolution for roll measurements.
• The system's performance, validated experimentally, surpasses conventional techniques.
• This advancement has potential implications for industries requiring high-precision metrology.