Propagation and amplification of ultrashort light pulses in a resonant two-level medium: finite-difference time-domain analysis

Propagation and amplification of an ultrashort laser pulse in a two-level m edium is numerically investigated with the use of the finite-difference tim e-domain (FDTD) procedure simultaneously solving Maxwell and Schrodinger eq uations with no assumptions characteristic of slowly varying envelope appro ximation. Comparison of the results of FDTD numerical simulations with the predictions of the pulse area theorem has demonstrated that the developed n umerical procedure provides an adequate description of pulse evolution in a two-level medium. Amplification of ultrashort light pulses in a two-level medium is analyzed. Two methods of improving the gain of ultrashort pulses in a two-level medium by modulating the spatial distribution of dipole mome nts of resonant transitions and using initially chirped frequency-detuned p ulses are explored. (C) 2001 Elsevier Science B.V. All rights reserved.