Medium-finesse optical cavity for the stabilization of Rydberg lasers.

Area of Science:

• Atomic, Molecular, and Optical Physics
• Quantum Optics
• Laser Spectroscopy

Background:

• Precise laser frequency control is essential for experiments involving ultracold Rydberg atoms.
• Achieving a laser linewidth comparable to the natural Rydberg linewidth (≈10 kHz) is a key experimental requirement.
• Existing methods may lack the necessary stability, robustness, or affordability for widespread application.

Purpose of the Study:

• To design, construct, and characterize a medium-finesse Fabry-Perot cavity.
• To enable simultaneous frequency stabilization of two lasers at 960 nm and 780 nm.
• To reduce laser linewidths below the target 10 kHz for Rydberg atom experiments.

Main Methods:

• Fabrication of a medium-finesse Fabry-Perot cavity with a finesse of approximately 1500.
• Utilization of an ultra-low expansion (ULE) glass spacer for the cavity.
• Implementation of active temperature stabilization for the ULE glass spacer.

Main Results:

• The Fabry-Perot cavity successfully reduced the linewidth of the 960 nm and 780 nm lasers.
• Active temperature stabilization of the ULE spacer limited residual frequency drift to less than 1 MHz/day.
• The cavity design prioritized ease of construction, robustness, and cost-effectiveness.

Conclusions:

• The developed Fabry-Perot cavity provides a stable and reliable platform for frequency-stabilizing lasers for Rydberg atom research.
• The system achieves the desired narrow laser linewidths, enabling high-precision atomic experiments.
• The design offers a practical and affordable solution for researchers in ultracold atom physics.