Optical soliton amplification : adiabatic approximation

Sandra Eix

Richard David Hochman

Vladimir D Taranukhin, M. Yu. Pogosbekyan

The amplification of intense light pulses in resonance active media with an optical Stark effect and coherence effects is examined theoretically. In the course of the amplification, the pulse may go through a stage of an incoherent Stark quasisoliton. The envelope of this quasisoliton has an approximately constant, highly asymmetric shape. The energy of the quasisoliton is approximately constant. Upon further amplification, the Stark quasisoliton "breaks up" into a train of shorter pulses. Over a sufficiently long amplification distance, a true soliton may form in the active medium. In general, this true soliton is not the same as a standard π pulse in a medium without a Stark effect.

T. Yu. Golubeva, Yu. M. Golubev, Sergey V. Fedorov +3 more

The Heisenberg-Langevin equation for a spatial laser soliton in a wide-aperture laser with saturable absorption is constructed within the framework of consistent quantum electrodynamics. We discuss in detail the canonical variables for the generation field and the material two-level medium, consisting of centres providing amplification and absorption. It is assumed that laser generation evolves in time much more slowly than an atomic media. This assumption makes it possible to apply the adiabatic approximation and construct a closed equation for the amplitude of a laser field. Much attention is paid to the formulation of Langevin sources when deriving the equation since they play a decisive role in the formation of solitons' quantum statistical features. To provide an appropriate procedure for observing the quantum squeezing of a soliton, synchronization of laser generation by an external weak electromagnetic field is considered. Here we also present the results of the analysis of a classical laser soliton (neglecting the quantum fluctuations), which serves as the basis for further consideration of quantum effects.

Nobuya Maeshima, Kosuke Moriya, Ken-ichi Hino

We investigate optical properties of polarons and solitons in one-dimensional (1D) Peierls–Hubbard model by using the density matrix renormalization group method combined with the adiabatic approximation for lattice distortion. Obtained numerical results demonstrate that there appear novel midgap peaks in optical response spectra of polarons and charged-solitons for large on-site Coulomb interaction U . The origins of these novel peaks are understood in terms of charge-transfer excitations within clusters for each states: a dimer in polarons and a pentamer in charged-solitons, both of which are located around the center of the relaxed lattice distortion.

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