Interference-enhanced and power-reduced CPT atomic realization approach with an external cavity

Area of Science:

• Atomic, Molecular, and Optical Physics
• Quantum Optics
• Metrology

Background:

• Coherent Population Trapping (CPT) is a quantum interference effect used in atomic clocks.
• Conventional CPT atomic clocks face limitations in signal strength and power efficiency.
• External cavities can enhance light-atom interactions in atomic clock designs.

Purpose of the Study:

• To investigate a novel CPT atomic clock scheme utilizing an external cavity.
• To enhance the CPT signal magnitude and improve modulation efficiency.
• To explore the potential for low-power atomic clock applications.

Main Methods:

• Implementation of a CPT scheme with counterpropagating circularly polarized lasers.
• Formation of an external cavity using a vertical-cavity surface-emitting laser (VCSEL) and a partially reflecting mirror.
• Cancellation of spin-polarized dark states to enhance interaction with atoms.

Main Results:

• Achieved a CPT signal eight times larger than conventional schemes.
• Demonstrated CPT resonance excitation at lower microwave power, improving modulation efficiency.
• Experimental validation of the enhanced CPT signal and lower power requirements.

Conclusions:

• The proposed external cavity CPT scheme significantly enhances signal strength.
• The scheme offers improved modulation efficiency, enabling operation at lower microwave power.
• This approach presents a viable alternative for developing advanced, low-power atomic clocks.