Compact plug and play optical frequency reference device based on Doppler-free spectroscopy of rubidium vapor

Area of Science:

• Atomic, Molecular, and Optical Physics
• Laser Spectroscopy
• Metrology

Background:

• Compactness, robustness, and autonomy are crucial for optical frequency references in mobile, ground, and space systems.
• Existing optical frequency standards often lack the required portability and ease of use for diverse applications.

Purpose of the Study:

• To present a standalone, plug-and-play optical frequency reference device.
• To achieve high frequency stability in a compact, autonomous module for mobile applications.

Main Methods:

• Utilized frequency modulation spectroscopy targeting the D2-transition of rubidium at 780 nm.
• Employed a micro-integrated laser-optical bench for a hand-sized module.
• Investigated thermal characteristics influencing output frequency and applied Bayesian optimization for stability enhancement.

Main Results:

• Developed a fully autonomous, hand-sized laser module operating after a single button press.
• Generated 6 mW of frequency-stabilized light with a relative frequency instability of 1.4×10^-12 at 1 s.
• Achieved frequency instability below 10^-11 at 10⁵ s averaging time.

Conclusions:

• The presented device meets the requirements for compact, robust, and autonomous optical frequency references.
• Demonstrated the feasibility of high-performance frequency stabilization in a portable module.
• The device is suitable for reliable operation in mobile systems, including ground-based and space applications.