Lorenz character of the Doppler-broadened far-infrared laser (original) (raw)
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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.
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
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.
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
Self pulsing properties of optically pumped FIR NH3 lasers
Applied Physics B Photophysics and Laser Chemistry, 1987
We report on measurements of periodic and chaotic self-pulsing beyond the second threshold of far-infrared NH3 lasers. While the instabilities of the 81 gm 14NH3 laser follow a simple pattern, for the 374 gm 15NH3 laser different pulsing properties are found in different parameter ranges. Pulses under conditions of high pumping power are measured in detail, in view of possible applications of these coherent, high-repetition rate far-infrared pulsed lasers.
Optics Communications, 1995
Numerical studies of the laser-Lorenz model using parameters reasonably accessible for recent experiments with a single mode homogeneously broadened laser demons~ate that the form of the return map of successive peak values of the intensity changes from a sharply cusped map in resonance to a map with a smoothly rounded maximum as the laser is detuned into the period doubling regime. This transformation appears to be related to the disappearance (with detuning) of the heterocbnic structural basis for the stable manifold which exists in resonance. This is in contrast to the evidence reported by Tang and Weiss (Phys. Rev. A 49 ( 1994) 1296) of a cusped map for both the period doubling chaos found with detuning and the spiral chaos found in resonance for seemingly Lorenz-like behavior of the far-infrared ammonia laser from which it was concluded that there existed a "unique chaotic attractor for a single-mode laser". Natzaret-Oliva s/n, . 0030-4018/95/$09.50 0 1995 Elsevier Science B.V. All rights reserved SSLNOO30-4018(95)00087-9
Narrow gain spikes and frequency pulling in the midinfrared ammonia laser
IEEE Journal of Quantum Electronics, 1991
The gain of a 12 pm NH, laser transition, optically pumped by CO2 laser radiation, has been measured under wellcharacterized conditions. Good agreement is found between the measured gain and theoretical calculations based on a threelevel density matrix formalism. The theory was also employed to explain the stable frequency behavior of the NH3 laser.