Polarization stability and dynamics in a model for a polarization-isotropic laser that goes beyond third-order Lamb theory

Abstract

Instabilities and dynamical pulsations are common features of solutions of a model that includes the material variable dynamics for a laser with a polarization isotropic resonator and with a homogeneously broadened jϭ1→ jϭ0 transition. These resemble in some respects features found in third-order Lamb theories under anisotropic conditions, such as splitting of the optical field into two relatively independent orthogonally polarized modes with different optical frequencies. At higher intensities the amplitudes and frequencies of these modes exhibit such strong coupling that a ''two-mode'' description loses its usefulness or effectiveness. Various periodic attractors with strong intensity and polarization pulsations are found for moderate excitation levels. Some of these attractors preserve the breaking of the polarization isotropy on average just as does any linearly polarized solution. But in some cases the dynamics restore the polarization isotropy on average. We also find other dynamical phenomena, including periodic and apparently chaotic states, often involving rapid switching between long interludes of nearly constant polarization, and homoclinic behavior.

Polarized optical feedback and noise effects on CO2laser polarization dynamics: spatial and temporal behavior

“…The c parameter represents the coherence decay rate, whose value should be chosen between per and II [1]. This parameter cannot be directly measured, but an extensive comparison between simulation and experiment allowed us to deduce an effective value c % II in all cases, which is also consistent with the observation that just linearly polarized states are found in the experiment [9].…”

“…All of these possible effects behave as an effective noise that is at the base of the observed bistability. This behavior cannot be faithfully reproduced with a static linear loss parameter, which is the usual form in the literature [1]. Then, in our model the linear anisotropy parameter is included as a noise.…”

“…The fields will be decomposed in a circularly polarized basis. The resulting two-level Maxwell-Bloch equations can be written as [1,7,9] …”

“…Then, in our model the linear anisotropy parameter is included as a noise. Finally, the model reads as [1,9,11] …”

“…However, in perfectly cylindrical laser cavities without any elements to select a preferred polarization, the study of the dynamics includes the necessity of considering the vector nature of the electric field. The polarization dynamics of an isotropic laser have been dealt with in several theoretical works, pointing out the important role played by the material variables in the selection of the polarization state [1]. In particular, the degeneracy of the angular momentum states of the laser transition sublevels has been considered as the coupling source between different polarization states.…”