RESONANT PULSE EXCITATION LEADING TO IONIZATION

Laser excitation of a two-level atom is analytically studied for arbitrary pulse shape, area, and energy. The ionization mechanism is modeled as a homogeneous width of the atomic excited state. A transformation of the optical Bloch equations allows the dynamics to be completely described by a single equation for the area of the pulse at time t, (t). Analytic solutions for the total bound population for a wide variety of pulse shapes can be found in two regions: (t)sin(t) and (t)>, where (t) is the resonance Rabi frequency. The generalization of the two-level atom results to the N-level atom is discussed. © 1978 The American Physical Society.