Laser locking to the 199Hg 1S0-3P0 clock transition with 5.4 × 10(-15)/✓τ fractional frequency instability

Area of Science:

• Atomic Physics
• Quantum Metrology
• Laser Spectroscopy

Background:

• Optical lattice traps and the Lamb-Dicke regime are crucial for high-precision atomic spectroscopy.
• Atomic clock transitions provide fundamental frequency standards.
• Laser stabilization is key to achieving high precision in measurements.

Purpose of the Study:

• To develop an ultrastable laser locked to the 1S0-3P0 transition of 199Hg atoms.
• To characterize the frequency instability and drift of the stabilized laser system.
• To compare the performance of independent laser stabilization systems.

Main Methods:

• Confining 199Hg atoms in an optical lattice trap operating in the Lamb-Dicke regime.
• Utilizing an ultranarrow spectral line at 265.6 nm (FWHM ~15 Hz) for laser locking.
• Employing a 1062.6 nm fiber laser locked to an ultrastable optical cavity.

Main Results:

• Achieved a fractional frequency instability of 5.4×10(-15)/✓τ for τ ≤ 400 s.
• The ultrastable optical cavity exhibited a mean drift rate of -6.0×10(-17) s⁻¹.
• Comparison of two independent systems showed flicker noise limited instability of 4×10(-16) per cavity.

Conclusions:

• The 199Hg 1S0-3P0 transition provides a robust reference for ultrastable laser development.
• The demonstrated laser stabilization achieves high performance suitable for advanced metrology.
• Independent optical cavities show comparable performance, validating the system's reliability.