High-efficiency electro-optic lens for radio-frequency beam wavefront modulation for mode mismatch sensing.

Area of Science:

• Optics and Photonics
• Experimental Physics
• Gravitational Wave Astronomy

Background:

• Optimal coupling in optical cavities is crucial for experiments like interferometric gravitational wave detectors.
• Active mode mismatch sensing and control are key to achieving this optimal coupling.

Purpose of the Study:

• To demonstrate a novel radio-frequency (RF) beam wavefront curvature modulation-based mode mismatch sensing scheme.
• To provide guidance for designing beam profiles to enhance electro-optic lens (EOL) modulation efficiency.

Main Methods:

• Utilizing an electro-optic lens (EOL) for beam wavefront curvature actuation.
• Employing a mode converting telescope to generate a detectable mode mismatch signal.
• Analytical and numerical investigation of second-order mode generation from wavefront actuation.

Main Results:

• The proposed scheme effectively generates a non-vanishing mode mismatch sensing signal.
• Second-order mode generation is analyzed concerning Gaussian beam size evolution and phase mismatch cancellation.
• The study quantifies second-order mode generation based on incident beam waist and EOL crystal size.

Conclusions:

• The developed RF beam wavefront curvature modulation scheme offers a viable method for active mode mismatch sensing.
• Understanding the trade-offs between beam size, crystal size, and clipping loss is essential for optimizing EOL modulation efficiency.
• This work contributes to improving the precision of optical cavity experiments, particularly in gravitational wave detection.