Active Faraday optical frequency standard.

Area of Science:

• Atomic, Molecular, and Optical Physics
• Metrology and Measurement Science

Background:

• Optical atomic clocks are crucial for precise timekeeping and fundamental physics research.
• Cesium vapor serves as a key atomic system for frequency standards due to its well-defined transitions.

Purpose of the Study:

• To propose and experimentally demonstrate an active Faraday optical clock mechanism.
• To establish a novel optical frequency standard utilizing a narrow bandwidth Faraday atomic filter.

Main Methods:

• Employing velocity-selective optical pumping of cesium vapor.
• Utilizing the cesium 6 (2)S(1/2) F=4 to 6 (2)P(3/2) F'=4 and 5 crossover transition line for frequency determination.
• Performing optical heterodyne beat measurements between independent setups.

Main Results:

• Achieved a frequency linewidth of 281(23) Hz, which is 1.9×10(4) times narrower than the natural linewidth of the cesium 852-nm transition.
• Demonstrated a maximum emitted light power of 75 μW.
• Validated the narrow linewidth and reduced cavity pulling advantages of the active Faraday optical frequency standard.

Conclusions:

• The developed active Faraday optical frequency standard offers significant improvements in linewidth and cavity pulling.
• The proposed mechanism is extendable to other alkali and alkaline-earth metal atoms.
• This technology holds promise for the development of next-generation optical atomic clocks.