Rabi oscillations at three-photon laser excitation of a single rubidium Rydberg atom in an optical dipole trap

TL;DR

This paper reports the first observation of three-photon Rabi oscillations in a single rubidium Rydberg atom within an optical dipole trap, demonstrating control over atomic states using intense laser fields for quantum information applications.

Contribution

It introduces the experimental realization of three-photon Rabi oscillations in a single atom and explores laser control techniques affecting coherence and transition dynamics.

Findings

Rabi oscillations observed at frequencies of 1-5 MHz

Coherence times achieved are around 0.7-0.8 microseconds

Laser intensity influences Rabi frequency and transition control

Abstract

In an experiment on three-photon laser excitation $5S_{1/2} \to 5P_{3/2} \to 6S_{1/2} \to 37P_{3/2}$ of a single $^{87}$Rb Rydberg atom in an optical dipole trap, we have observed for the first time three-photon Rabi oscillations between the ground and the Rydberg states. The single atom was detected optically by measuring the signal of resonant fluorescence with a low-noise sCMOS video camera. Relative probability of the atom to remain in the trap after the action of three synchronized laser excitation pulses was measured for their durations varied in the range from 100 ns to 2 $\mu$s. A specific feature of the experiment was the usage of intense laser radiation at the wavelength of 1367 nm on the second excitation step, which provided the single-photon Rabi frequency up to 2 GHz to control the effective detunings of the intermediate levels of the three-photon transition due to ac Stark effect. We have detected Rabi oscillations with frequency from 1 to 5 MHz depending on the intensities of the laser pulses on the first and the second excitation steps with the coherence time of 0.7-0.8 $\mu$s. The ways to increase the coherence time and contrast of the three-photon Rabi oscillations for applications in quantum information processing with Rydberg atoms are discussed.