Small displacement measurements based on an angular-deviation amplifier and interferometric phase detection

Area of Science:

• Metrology
• Optical Measurement
• Nanotechnology

Background:

• Accurate measurement of small displacements is crucial in various scientific and industrial fields.
• Traditional interferometry methods face limitations in sensitivity and accuracy for micro-displacements.

Purpose of the Study:

• To develop a highly sensitive method for measuring small displacements.
• To enhance the accuracy and performance of displacement detection using optical principles.

Main Methods:

• A common-path heterodyne interferometry system detects phase changes induced by angle deviation from displacement.
• An angular amplifier magnifies angle deviations, and a surface plasmon resonance (SPR) sensor boosts phase detection performance.
• Light reflection N times amplifies the angular deflection, leading to an N-times amplified phase shift.

Main Results:

• The proposed method achieves displacement measurement sensitivity as low as 0.13 μm without an SPR sensor and 0.08 μm with an SPR sensor.
• The measurement system demonstrates a maximum measurement range of 1000 μm.
• The accumulated phase shift is directly proportional to the amplified angle deviation and displacement.

Conclusions:

• The developed method offers a significant improvement in small displacement measurement accuracy and sensitivity.
• Integration of angular amplification and SPR sensing provides a robust platform for high-precision metrology.
• This technique holds potential for applications requiring ultra-precise motion detection.