Chaotic Laser Mode

Based on an analysis of the characteristics of chaotic laser radiation, we introduce the notion and notation of a chaotic laser mode. Within a semiclassical model of single-mode laser generation with modulated injection of an external coherent field we derive conditions for the onset and maintenance of stable chaotic generation in the form of parameter intervals of the external field. For these regimes we analyze measurable radiation characteristics – envelope amplitude and frequency, degree of monochromaticity, coherence time, coherence length and coherence area, beam divergence and transverse intensity distribution – and show that all of them exhibit chaotic temporal dynamics. We discuss the capabilities and limitations of Fourier spectral analysis of broadband chaotic signals and demonstrate that, when combined with fractal analysis of the radiation spectrum, this approach allows one to determine the interval and evolution of the instantaneous frequency and intensity and to distinguish chaotic regimes from stochastic and quasiperiodic ones. On this basis we define a chaotic mode as a globally stable, distinguishable and reproducible type of chaotic oscillation in a nonlinear dynamical system; the results can be used for the design of laser systems with controlled chaotic generation for secure optical communications, sensing and metrology.