Rb vapor-cell clock demonstration with a frequency-doubled telecom laser

Area of Science:

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

Background:

• Atomic clocks are crucial for precise timekeeping and navigation.
• Rubidium (Rb) vapor-cell clocks offer a compact and cost-effective solution.
• Laser noise and ac Stark shifts are key limitations in clock performance.

Purpose of the Study:

• To evaluate a novel low-noise telecom laser system for Rb vapor-cell atomic clocks.
• To investigate the impact of laser amplitude/frequency noise and ac Stark shift on clock stability.
• To demonstrate the suitability of frequency-doubled telecom lasers for high-performance atomic clocks.

Main Methods:

• Utilized a continuous-wave double-resonance scheme with a 1.56 μm telecom laser.
• Frequency-doubled the telecom laser output to the appropriate atomic transition wavelength.
• Quantitatively measured laser noise contributions and ac Stark shift effects on clock stability.

Main Results:

• Achieved a short-term clock instability of 2.5·10^-13·τ^-1/2, a first for frequency-doubled telecom lasers.
• Demonstrated a threefold improvement in short-term clock stability compared to a direct 780-nm laser.
• Identified and quantified the primary noise sources limiting short-term frequency stability.

Conclusions:

• Frequency-doubled low-noise telecom lasers are suitable for high-performance Rb vapor-cell clocks.
• The developed laser system significantly enhances clock stability by mitigating noise and shifts.
• This work paves the way for more robust and stable compact atomic clock technologies.