Transverse effects and self-pulsing in optical bistability (original) (raw)

Dispersive optical bistability in a ring cavity

Optics Communications, 1978

Equations governing the behaviour of a single mode high-Q ring cavity are obtained for a coherent driving field (detuned to both cavity and atoms) and inhomogeneously broadened atomic transitions using a Hamiltonian approach. We find the region of bistability and critical points in the homogeneous broadening case. Numerical results including inhomogeneous broadening show that bistability is obtained more readily by detuning both the atomic transition and the cavity mode relative to the driving field.

Inhomogeneous and transverse field effects on time delayed optical bistability inside and outside the rotating wave approximation

This paper is concerned with non-autonomous Maxwell-Bloch equations when subject to a time delay. We investigate the dynamical behavior of an optical bistable system for inhomogeneous Lorentzian broadening and transverse Gaussian field effects interacting with a single mode ring cavity both inside and outside the rotating wave approximation. Results show that the known bistable behavior of the device can be affected by instabilities. However, in some cases, for instance when the incident Gaussian laser beam waist is less than that of cylindrical atomic sample, a large butterfly hysteresis is demonstrated in the fundamental field component. As far as the authors are aware, this is the first time that such behavior has been demonstrated.

Multimode instability in optical bistability

Physical Review A, 1989

We compare theoretical predictions and experimental data for the multimode instability of optical bistability, which arises from the coherent dynamics of a system of two-level molecules contained in an optical cavity and driven by an external stationary laser field. Considerable insight into this phenomenon is provided by two "rules of thumb" that govern the behavior of the self-pulsing frequency, and establish its relation with the Rabi frequency of the intracavity field. We describe in detail the experimental apparatus and the main features of the experimental findings. The theoretical results are based on the Maxwell-Bloch equations for a ring cavity in the plane-wave approximation. Despite the crudeness of this model, the numerical data display a satisfactory qualitative agreement with the experimental results. Additional period-doubling and chaotic phenomena, predicted by the theory and not observed in the experiment, are presumably washed out by the longitudinal and radial variation of the electric field in the cavity. nally, in condition (2) one must take into account the power broadening in the atomic line. On the other hand, a MM instability can arise only if the power-broadened atomic linewidth is on the order or larger than the free spectral range; this condition requires a large atomic linewidth and/or a long cavity, and is not satisfied in the standard homogeneously broadened alloptical systems which meet the conditions for the twolevel-system description. This feature makes it very difficult to observe experimentally MM instabilities which arise from the interplay of different longitudinal modes, unless one uses a hybrid system which includes a delay line. ' Single-mode and multimode instabilities are linked by precise correspondence principles demonstrated in Ref. 17, which provides a fundamental justification of the socalled "weak-sideband approach, " that is often used in the interpretation and discussion of optical instabilities. ' This approach ascribes the rise of the instability to the gain experienced by the various modes, which 39 703

Optical bistability with symmetry breaking

Physical Review A, 1984

It is shown that a simple system without a cavity exhibits optical bistability with no hysteresis but with symmetry-breaking or pitchfork bifurcation. The optical system is composed of a cell containing atoms with spin in the ground state, a A,/8 plate and a mirror, and an incident light beam linearly polarized and nearly resonant with the atomic absorption line. The system has a positivefeedback loop for the rotation of polarization through competitive optical pumping by a+ circularly polarized components. %hen the intensity of the incident light exceeds a critical value, symmetry breaking occurs and its polarization is subject to rotation in the clockwise or anticlockwise sense. Correspondingly, atomic spin polarization is produced spontaneously in a direction parallel or antiparallel to the incident beam. This new type of optical bistability is found to be explained well in context with the cusp catastrophe, as well as the ordinary one with hysteresis. It is also found that, in the presence of a transverse magnetic field, self-sustained spin precession occurs, which results in the steady-state modulation of the light polarization at about the Larmor frequency. Experimental evidence of the symmetry breaking and pitchfork bifurcation is obtained by using sodium vapor.

Optical bistability in sideband output modes induced by a squeezed vacuum

Physical Review A - Atomic, Molecular, and Optical Physics, 2004

We consider N two-level atoms in a ring cavity interacting with a broadband squeezed vacuum centered at frequency s and an input monochromatic driving field at frequency . We show that, besides the central mode (at ), an infinity of sideband modes are produced at the output, with frequencies shifted from by multiples of 2͑ − s ͒. We analyze the optical bistability of the two nearest sideband modes, red shifted and blue shifted.

Space and time-dependent effects in optical bistability

Optics Communications, 1979

We present numerical studies of optical bistability which admit variations in both space and time in the governing cnumber equations. We justify mean field theory for both the steady state and time dependent regimes for low enough cavity transmissivity T: but for T) 0.2 mean field theory is scarcely applicable. Higher harmonic fields are important at low T (high reflexion). As expected the steady state hysterisis behaviour at low T is considerably modified in the time dependent regime. Transistor action at high T ~ 0.9 is described. In general the numerical results show good qualitative agreement with the experiment of Gibbs et al.

Dynamical nonlinear optics and bistability

Applied Physics B Photophysics and Laser Chemistry, 1982

When the Rydberg atoms are prepared in the upper level of a transition resonant with the cavity mode, they amplify the Nackbody radiation at the corresponding frequency, and, above a given threshold, emit a transient maser pulse. We have conted the number n of atoms transferred by this process at time t following the laser pumping pulse in the lower level of the maser transition. We experimentally determine the probability P(n, t) of finding n atoms transferred at time t, n being of course equal to the number of photons in the field at that time. For t short enough, the P(n, t) law is found to be an exponentially decaying function of n, a distribution typical of an amplified blackbody radiation field. At longer times t, the distribution changes its shape and becomes a bell-shaped function centered around a n4;0 value, which is characteristic of a coherent emission. The observed probability laws are in very fair agreement with the theoretical ones [2].

Self-pulsing in intrinsic optical bistability with two-level molecules

Physical Review Letters, 1988

Well-developed sine-wave self-pulsing has been observed in the beam transmitted by a passive cavity containing a molecular gas, subjected to a cw incident beam. The free spectral range of the cavity is comparable to the Rabi frequency inside the cavity and much larger than the relaxation rate. The selfpulsing is attributed to the multimode instability predicted by Bonifacio and Lugiato in 1978 but not yet observed.