A two-axis tilt control system on a turntable for rotating-optical-cavity experiments

Area of Science:

• Experimental Physics
• Precision Measurement
• Fundamental Symmetries

Background:

• Precision measurements, such as tests of Lorentz invariance, often require highly stable platforms.
• Rotating optical cavities are sensitive to tilt variations, necessitating effective stabilization systems.

Purpose of the Study:

• To develop and implement a single-stage tilt control system for a rotating platform.
• To suppress tilt variations in two orthogonal directions for an experiment testing Lorentz invariance using optical cavities.

Main Methods:

• Utilized home-built voice-coil actuators, a tilt sensor, and control electronics for active tilt suppression.
• Investigated and compensated for cross-coupling effects between orthogonal axes.
• Employed a compensating weight to resolve loop instability.

Main Results:

• Reduced tilt variation from ±30 µrad to within ±0.2 µrad for each axis.
• Observed a residual tilt component of 0.1 µrad at the rotational frequency.
• Calculated a systematic offset of 1.8 × 10^-17 for the Lorentz violating parameter κ_e-^ZZ.

Conclusions:

• The developed tilt control system effectively stabilizes rotating platforms for precision experiments.
• Further improvements using piezo-electric actuators could reduce systematic offsets to 1.8 × 10^-18.
• The system demonstrates significant progress in achieving the stability required for fundamental symmetry tests.