INSTABILITIES IN DOPPLER BROADENED OPTICALLY PUMPED FAR-INFRARED LASERS (original) (raw)

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.

Homoclinic orbits and chaos in a multimode laser

Journal of the Optical Society of America B, 1997

We show experimentally that under certain conditions the chaotic intensity dynamics of an optically pumped NH 3 bidirectional ring laser could be well described in terms of Shil'nikov homoclinic orbits and chaos. We found that the mechanism that resulted in this kind of dynamics of the laser is the competition between effects caused by the mode interaction between the forward and the backward modes of the laser and by the intrinsic single-mode dynamics of the interacting modes.

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.

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.

Influence of light polarization on the dynamics of optically pumped lasers

Physical Review A, 1990

The dynamic behavior of a coherently pumped ring laser with a homogeneously broadened four-level medium is analyzed theoretically, considering linearly polarized pump and generated laser beams. The laser is shown to be much more stable when these polarizations are parallel than when they are orthogonal. In the latter case the instability pump threshold can be as low as four times the first laser threshold, and the laser dynamics shows Lorenz-type features. Recent experimental studies of self-pulsing in an optically pumped FIR single-mode ammonia laser showed for the first time Lorenz-like behavior in the real world. ' The theoretical interpretation of these results raises conceptual difficulties, however, since the FIR laser experiments are a priori more complicated than the simple twolevel homogeneously broadened medium interacting with a single mode of a unidirectional ring cavity, which is considered in the Lorenz-Haken model. Recently, we have shown that a more appropriate Doppler-broadened threelevel laser model can explain the appearance of Lorenzlike dynamics in an optically-pumped

Bi-instability and the global role of unstable resonant orbits in a driven laser

Physica D: Nonlinear Phenomena, 2000

Driven class-B lasers are devices which possess quadratic nonlinearities and are known to exhibit chaotic behavior. We describe the onset of global heteroclinic connections which give rise to chaotic saddles. These form the precursor topology which creates both localized homoclinic chaos, as well as global mixed-mode heteroclinic chaos. To locate the relevant periodic orbits creating the precursor topology, approximate maps are derived using matched asymptotic expansions and subharmonic Melnikov theory. Locating the relevant unstable fixed points of the maps provides an organizing framework to understand the global dynamics and chaos exhibited by the laser.

Chapter 9. Chaotic dynamics of the vibronic laser

Recent Achievements in Laser Dynamics: Control and Synchronization , 2008

Herewith we present the nonlinear dynamics of a very interesting group of lasers, e.g. vibronic lasers, where due to the pump-dependent population of the lattice phonons, the photon energy of the pump serves as the control parameter. Experimental results and the theoretical predictions are compared for the particular case of the alexandrite laser. We discuss its rich dynamics including homoclinic chaos, small-scale chaos and crisis, the possibility of modulation control, the cavity length control and the optical feedback scheme of chaos control.