Hyperpolarizability and Operational Magic Wavelength in an Optical Lattice Clock

Area of Science:

• Atomic, Molecular, and Optical (AMO) Physics
• Metrology and Precision Measurement

Background:

• Optical clocks rely on tightly confined atoms for enhanced accuracy.
• Frequency shifts due to atomic confinement can degrade clock performance.
• Theoretical models predict nonlinear scaling of shifts with optical lattice trap depth.

Purpose of the Study:

• To experimentally observe and constrain predicted nonlinear frequency shifts in an Ytterbium-171 (¹⁷¹Yb) optical lattice clock.
• To investigate the impact of trap depth on clock frequency shifts.
• To identify conditions for minimizing or eliminating these systematic errors.

Main Methods:

• Construction of a lattice enhancement cavity to amplify light shifts.
• Experimental measurement of atomic temperature dependence on optical trap depth.
• Analysis of frequency shifts across varying trap depths in the ¹⁷¹Yb optical lattice clock.

Main Results:

• Observed atomic temperature is proportional to the optical trap depth.
• Demonstrated a fundamental alteration in the scaling of trap-induced light shifts.
• Identified an
• operational
• magic wavelength where frequency shifts are insensitive to trap depth variations.

Conclusions:

• The experimental characterization of light shifts is essential for achieving 10⁻¹⁸ clock precision.
• The identified operational magic wavelength offers a pathway to mitigate systematic errors.
• These findings provide critical data for the development of next-generation optical atomic clocks.