Excitation of a single atom with exponentially rising light pulses

TL;DR

This study demonstrates that exponentially rising light pulses more effectively excite a single atom than square pulses, achieving near-saturation with few photons and observing Rabi oscillations at higher photon counts.

Contribution

It provides experimental evidence that exponentially rising pulses enhance atomic excitation efficiency compared to traditional square pulses, aligning with a time-reversed Weisskopf-Wigner model.

Findings

Higher excitation probability with rising exponential pulses

Achieved near-saturation with ~50 photons

Observed Rabi oscillations with ~1000 photons

Abstract

We investigate the interaction between a single atom and optical pulses in a coherent state with a controlled temporal envelope. In a comparison between a rising exponential and a square envelope, we show that the rising exponential envelope leads to a higher excitation probability for fixed low average photon numbers, in accordance to a time-reversed Weisskopf-Wigner model. We characterize the atomic transition dynamics for a wide range of the average photon numbers, and are able to saturate the optical transition of a single atom with ~50 photons in a pulse by a strong focusing technique. For photon numbers of ~1000 in a 15ns long pulse, we clearly observe Rabi oscillations.