Self-Organized Bottleneck and Coexistence of Incongruous States in a Microwave Phonon Laser (Phaser)

Phenomena of emergence of regular and chaotic fine structure (FS) in stimulated emission (SE) power spectra of an autonomous microwave phonon laser (phaser) have been revealed and investigated experimentally in pink ruby at liquid helium temperatures. The phenomenon of a selforganized bottleneck in evolution of the microwave acoustic FS lines has been observed by means of narrow-range phonon SE spectral analysis. The large-scale phenomenon of coexistence of incongruous (stationary, periodic and chaotic) states in the whole spin-phonon phaser system is revealed in experiments with panoramic power spectra of phonon SE. Phaser active medium is characterized by a very small ratio R = Tf/Ta << 1 (see D. N. Makovetskii, arXiv:cond-mat/0402640v1), where Tf is the lifetime of an emitted field quasiparticle (namely, acoustic branch phonon), and Ta is the time of spin-lattice relaxation of an individual active center (AC). Such the medium may be considered as an excitable system by analogy with class-B optical lasers (see C. O. Weiss e.a., Phys. Rev. A, vol.47, p.R1616, 1993), if one takes into account local (dipole-dipole) interactions between ACs. We propose a possible direction for modeling of both the observed phenomena on the basis of three-level cellular automata (S. D. Makovetskiy and D. N. Makovetskii, arXiv:cond-mat/0410460v2; S. D. Makovetskiy, arXiv:cond-mat/0602345v1) which emulate evolution of a bounded phaser-like excitable system with locally interacting ACs in the limit R→ 0.