Wide dynamic range homodyne interferometry method and its application for piezoactuator displacement measurements

Area of Science:

• Precision Engineering
• Optical Metrology
• Nanotechnology

Background:

• Multiactuated piezoelectric flextensional actuators (MAPFAs) are crucial for precision mechanics and nanotechnology.
• Optical interferometry is a key technique for characterizing nano/micro-displacements of such actuators.

Purpose of the Study:

• To develop an efficient homodyne phase detection method for high-dynamic-range displacement measurement.
• To characterize a novel XY nanopositioner MAPFA prototype using the developed interferometric technique.

Main Methods:

• Development of a homodyne phase detection method utilizing a Bessel functions recurrence relation.
• Analysis incorporating fading and electronic noise, using limited frequency spectrum data.
• Application of optical interferometry for displacement measurement and actuator characterization.

Main Results:

• Achieved a high dynamic range for phase demodulation (0.2 to 100π rad, equivalent to 10 nm to 16 μm displacement).
• Demonstrated a method requiring only magnitude spectrum data, without phase spectrum knowledge.
• Successfully tested a new XY nanopositioner MAPFA prototype for linearity, frequency response, and coupling.

Conclusions:

• The developed Bessel function-based interferometric method provides efficient and high-dynamic-range phase detection for MAPFAs.
• This technique effectively characterizes nanopositioner performance, addressing noise and fading challenges.
• The method offers practical advantages for nano/micro-displacement metrology in precision engineering.