Measurement of 1S-2S two-photon Rabi frequency of atomic hydrogen.

摘要

Three-photon ionization enhanced by two-photon resonance of the metastable 2S state of the hydrogen atom has been studied with a pulsed laser at 243 nm. Signals are detected by time-of-flight mass spectrometry. A new high power laser system has been developed for this work. It produces pulses that are tunable in the 243 nm spectral region and have high energy with Fourier transform limited linewidths. This is the first observation of saturation of the two-photon resonance with a narrow linewidth laser. Using a Monte Carlo method to simulate the laser system, we studied the dynamic process of hydrogen atoms in an intense pulsed laser field. The results shed light on the apparent disagreement between recent experimental data and theoretical calculations.