Coherent interaction of laser pulses in a resonant optically dense extended medium under the regime of strong field-matter coupling
- St. Petersburg State University, Department of Optics, Ulianovskaya 1, Petrodvorets, 198504 St. Petersburg (Russian Federation)
The nonstationary pump-probe interaction between short laser pulses propagating in a resonant optically dense coherent medium is considered. Special attention is paid to the case where the density of two-level particles is high enough that a considerable part of the energy of relatively weak external laser fields can be coherently absorbed and reemitted by the medium. Thus, the field of the medium reaction plays a key role in the interaction processes, which leads to collective behavior of an atomic ensemble in the strongly coupled light-matter system. Such behavior results in fast excitation interchanges between the field and a medium in the form of optical ringing, which is analogous to polariton beating in solid-state optics. This collective oscillating response, which can be treated as successive beats between light wave packets of different group velocities, is shown to significantly affect the propagation and amplification of the probe field under its nonlinear interaction with a nearly copropagating pump pulse. Depending on the probe-pump time delay, the probe transmission spectra show the appearance of either a specific doublet or coherent dip. The widths of these features are determined by the density-dependent field-matter coupling coefficient and increase during the propagation. Besides that, the widths of the coherent features, which appear close to resonance in the broadband probe spectrum, exceed the absorption-line width, since under the strong-coupling regime, the frequency of optical ringing exceeds the rate of incoherent relaxation. Contrary to stationary strong-field effects, the density- and coordinate-dependent transmission spectra of the probe manifest the importance of collective oscillations and cannot be obtained in the framework of a single-atom model.
- OSTI ID:
- 20640893
- Journal Information:
- Physical Review. A, Vol. 69, Issue 3; Other Information: DOI: 10.1103/PhysRevA.69.033804; (c) 2004 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1050-2947
- Country of Publication:
- United States
- Language:
- English
Similar Records
Technical Report: Final project report for Terahertz Spectroscopy of Complex Matter
Time-resolved THz studies of carrier dynamics in semiconductors, superconductors, and strongly-correlated electron materials
Related Subjects
ABSORPTION
AMPLIFICATION
ATOMS
COUPLING
DENSITY
EXCITATION
LASER RADIATION
LINE WIDTHS
NONLINEAR OPTICS
NONLINEAR PROBLEMS
OPTICAL PUMPING
OSCILLATIONS
PHOTON-ATOM COLLISIONS
PROBES
PULSES
RELAXATION
RESONANCE
SOLIDS
TIME DELAY
TRANSMISSION
VISIBLE RADIATION
WAVE PACKETS