Influence of light polarization on the dynamics of optically pumped lasers (original) (raw)
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Dynamics of coherently pumped lasers with linearly polarized pump and generated fields
Physical Review A, 1993
The inhuence of light polarization on the dynamics of an optically pumped single-mode laser with a homogeneously broadened four-level medium is theoretically investigated in detail. Pump and laser fields with either parallel or crossed linear polarizations are considered, as are typical in far-infraredlaser experiments. Numerical simulations reveal dramatically different dynamic behaviors for these two polarization configurations. The analysis of the model equations allows us to find the physical origin of both behaviors. In particular, the crossed-polarization configuration is shown to be effective in decoupling the pump and laser fields, thus allowing for the appearance of Lorenz-type dynamics. PACS number(s): 42.60.Mi, 42.50.Lc, 42.55.f
The dynamics of optically pumped molecular lasers. On its relation with the Lorenz-Haken model
Quantum and Semiclassical Optics, 1997
In this paper we review the work on dynamical instabilities in optically pumped molecular lasers (OPLs) that has been carried out during the last 15 years. The main purpose of this review article is to survey and extend the authors' work on optically pumped molecular lasers and to place it in context with other research done in this area, without being a comprehensive review of all previous work done on this topic. In particular, we concentrate on the theoretical interpretation of the Lorenz dynamics observed in the far-infrared ammonia laser by reviewing the results obtained with different models of OPLs. New results corresponding to the dynamics obtained with the Doppler-broadened OPL model are also given. In particular the influence of pump detuning is considered and we also provide a characterization of the chaotic dynamics that definitively clarifies its Lorenz character. Finally a critical account of the present understanding of the far-infrared ammonia laser experiments is given.
Journal of the Optical Society of America B, 1999
We study theoretically the dynamic behavior of a JЈ ϭ 1 → JЉ ϭ 0 laser (J is the angular momentum quantum number) optically pumped by means of a linearly polarized coherent field (coupled to an adjacent transition J ϭ 0 → JЈ ϭ 1) when the pump field polarization is rotated at a constant angular velocity ⍀ and the laser field polarization either is fixed by the cavity or is free (isotropic cavity). Because of a strong pumpinduced gain anisotropy, the dynamic behavior is completely different in each case. In the case of fixed laser field polarization, rich amplitude dynamics, which depend on the pump field strength, are found. At slow modulation frequencies (with respect to the molecular and the cavity relaxation rates), the system does not always follow the sequence of stationary and dynamic solutions that correspond to the autonomous laser as a function of the relative orientation angle between the polarizations of the pump and the laser fields. Phenomena such as delayed switching and suppression of chaos and stabilization of unstable steady states are found. In the case of an isotropic cavity, the pump field vector rotation is transferred to the laser field vector and amplitude unstable regimes are also strongly inhibited.
Lorenz character of the Doppler-broadened far-infrared laser
Journal of the Optical Society of America B, 1991
The dynamic behavior of an optically pumped Doppler-broadened single-mode far-infrared laser is theoretically investigated in detail and compared with that of the simpler Lorenz-Haken laser. Through the analysis of phase diagrams, three-dimensional attractor's projections, intensity maps, and the different terms of the laser equations, the analogies and the differences between the two models are determined. Optical pumping and Doppler broadening, present in this far-infrared laser model, can be approximately incorporated into a Lorenz-Haken model with effective parameters. These results represent a further step toward the understanding of the Lorenz-like behavior observed in recent years in the 81and 153-gm NH3 lasers.
Chaotic dynamics of an optically pumped NH_3 multitransverse-mode ring laser
Journal of the Optical Society of America B, 1996
We have experimentally studied the dynamics of an optically pumped NH 3 multitransverse-mode ring laser. We show that, because of the nonlinear interaction of transverse modes, the laser intensity output can be periodic, quasi-periodic, or chaotic. Depending on which transverse modes were involved in the interaction, two kinds of routes to chaos were observed in the laser. When four transverse modes interact, quasi-periodic chaos is found, whereas in the case when just two transverse modes with small frequency separation interact a period-doubling route to chaos at the mode beat frequency is observed. Metric properties of observed chaotic attractors were calculated.
Physical Review A, 2000
We have theoretically explored the behavior of a coherently pumped JЉϭ1→Jϭ0→JЈϭ1 isotropic cavity laser and compared it with the behavior of other related laser systems involving atomic or molecular levels with angular quantum numbers 0 and 1. It is shown that at low and moderate pumping strengths it behaves very differently from the JЉϭ0→Jϭ1→JЈϭ0 laser exhibiting no pump-induced gain anisotropy and allowing for linearly polarized ͑LP͒ solutions with arbitrary azimuth and circularly polarized ͑CP͒ solutions, depending on the values of the molecular relaxation rates. Above the instability threshold, a variety of dynamic regimes involving the polarization degree of freedom can be found, including LP states with rotating azimuth ͑as in incoherently pumped Jϭ0→JЈϭ1 or Jϭ1→JЈϭ0 lasers͒, antiphase dynamics, and full polarization chaos.
Lorenz-like chaos in NH3-FIR lasers
Infrared Physics & Technology, 1995
Studies of digitized recordings of periodic and chaotic intensity pulsations of an unidirectional far-infrared NH 3 ring laser at 81.5 ~m reveal common features (pulsing patterns, dimensions, entropies, and decay rates of the autocorrelation functions) to data sets numerically calculated from the Lorenz equations. The correspondence is striking. Nevertheless, there are small deviations of the experimental data to the numerical data which can, e.g. be explained as relics of counterpropagating waves in the ring laser and as influence of coherence effects from the coherently pumped three-level laser molecule.