High bandwidth frequency lock of a rigid tunable optical cavity

Area of Science:

• Optics
• Mechanical Engineering
• Gravitational Wave Astronomy

Background:

• Fabry-Perot cavities are crucial for high-precision measurements.
• Existing cavities may have limitations in bandwidth and noise performance.
• Gravitational wave detectors like LIGO and Virgo require advanced optical components.

Purpose of the Study:

• To develop a high bandwidth frequency lock for a tunable Fabry-Perot cavity.
• To utilize lead zirconate titanate (PZT) actuators for precise cavity control.
• To assess the noise performance of the cavity for interferometric applications.

Main Methods:

• Designed a rigid tunable Fabry-Perot cavity with a specific spacer.
• Implemented lead zirconate titanate (PZT) actuators for excitation.
• Achieved a first resonance frequency above 35 kHz for a 13 kHz servo-loop bandwidth.
• Measured noise added to the output beam relative to the input beam.

Main Results:

• Demonstrated a high bandwidth frequency lock of the tunable Fabry-Perot cavity.
• The cavity resonance frequency was designed to be above 35 kHz.
• A servo-loop bandwidth of 13 kHz was successfully achieved.
• Confirmed that the cavity adds no significant noise to the optical beam within the servo-loop bandwidth.

Conclusions:

• The developed PZT-actuated Fabry-Perot cavity offers high bandwidth frequency locking.
• The cavity's low noise addition makes it suitable for sensitive experiments.
• This technology can serve as a pre-mode cleaner in gravitational wave observatories like LIGO and Virgo.