High-Precision Ramsey-Comb Spectroscopy at Deep Ultraviolet Wavelengths

Area of Science:

• Atomic Physics
• Quantum Optics
• Spectroscopy

Background:

• High-precision spectroscopy is crucial for testing fundamental physics, including quantum electrodynamics and the proton radius puzzle.
• Deep ultraviolet (UV) and shorter wavelengths present significant experimental hurdles for precise measurements.

Purpose of the Study:

• To demonstrate Ramsey-comb spectroscopy in the deep UV for the first time.
• To showcase its capabilities for precision spectroscopy at short wavelengths.

Main Methods:

• Utilized Ramsey-comb spectroscopy in the deep UV.
• Excited the two-photon 4p^{6}→4p^{5}5p[1/2]_{0} transition of ^{84}Kr at 212.55 nm in an atomic beam.
• Employed a counterpropagating excitation geometry to minimize Doppler effects and effectively eliminated ac-Stark shifts.

Main Results:

• Achieved a transition frequency of 2,820,833,101,679(103) kHz for ^{84}Kr.
• The measurement uncertainty was reduced by a factor of 34 compared to previous best measurements.
• The precision was limited only by the 27 ns lifetime of the excited state.

Conclusions:

• Ramsey-comb spectroscopy is a viable and powerful technique for high-precision measurements in the deep UV.
• This advancement opens new avenues for fundamental physics tests requiring short-wavelength spectroscopy.