New type of breathers near Fermi resonance of optical oscillations in crystals

It has been shown that in crystals, near the Fermi resonance of optical exc itons, in addition to the solitons discovered before, such as multi-exciton bound complexes of cusp-, crater-, and dark-type possessing a single carri er frequency, amplitude, and envelope, there are nonlinear soliton excitati ons of a crucially new, breather-type. Such periodic soliton oscillations e xhibit slowly pulsing amplitudes of high-frequency oscillations, with the c arrier frequency being a multiple of the frequency of pulsations. In accord ance with the multiplicity, the depth of pulsations defines a series of the carrier frequencies, which are condensed near the basic frequency of optic al oscillations. The spatial dependence of the two envelopes of new soliton s of the cusp type is determined. With the increase in multiplicity, the sh arpness of the space envelope of a soliton decreases, while the localizatio n radius increases. Some other features of the solitons of new type are lis ted. (C) 2000 MAIK "Nauka/ Interperiodica".