Precision displacement measurement by active laser heterodyne interferometry.

Area of Science:

• * Physics
• * Optics
• * Metrology

Background:

• * Environmental disturbances can affect the accuracy of interferometric measurements.
• * Precision displacement measurement is crucial in various scientific and engineering fields.
• * Laser interferometry offers high sensitivity but is susceptible to external factors.

Purpose of the Study:

• * To develop an active laser heterodyne interferometer capable of automatic environmental disturbance compensation.
• * To achieve high-resolution precision displacement measurements.
• * To calibrate mirror displacement and measure piezoelectric transducer (PZT) hysteresis.

Main Methods:

• * Employed two Zeeman He-Ne lasers for heterodyne interferometry.
• * Utilized a piezomirror in a feedback loop for interferometer stabilization.
• * Tuned the wavelength of one laser to isolate displacement effects.
• * Used polarization optics to separate displacement and disturbance signals.

Main Results:

• * Demonstrated an active interferometer that automatically compensates for environmental disturbances.
• * Achieved precision displacement measurement with a resolution of +/-0.8 nm.
• * Successfully measured piezoelectric transducer (PZT) hysteresis over a 0.5 micrometer dynamic range.

Conclusions:

• * The developed active laser heterodyne interferometer effectively compensates for environmental disturbances.
• * The system enables high-resolution precision displacement measurements.
• * This technology is suitable for characterizing the dynamic behavior of devices like PZT transducers.