Theory of absorptive bistability

S. W. Koch, H.E. SCHMIDT, H. Haug

Ying Hua Ji, Fucheng Lin, Hua Xia +1 more

We investigate a general theory of optical bistability for a four-level system with single and triple states. Both absorptive and dispersive mechanisms are included. By solving the stable-state equation of a density matrix and using the mean-field approximation, we derive the state equation of bistability. The bistabilities with dispersion and absorption of single and triplet states, including pure dispersion and pure absorption, are numerically studied. The effects of cooperative parameters, resonant transition detuning, and cavity detuning parameters on bistable behavior are analyzed. We find that the absorption of triplet states is beneficial to dispersive bistability but is detrimental to absorptive bistability. The detuning of the resonant transition between single states is detrimental to bistability, whereas that between triplet states is beneficial to bistability. The structure of four levels with single and triplet states is a typicality of organic media. Our analysis is helpful for research into bistability devices of organic media.

N. M. Lawandy, R. Willner

The phenomenon of purely absorptive bistability is examined using a self-consistent multibeam interference method. A state equation is derived and shown to be identical to that derived from mean-field theory (MFT) in the limit of small absorption length products and high saturation. Using the theory given, we are able to examine the time evolution of the system analytically. The results show a critical slowing behavior near the bistable points of the system and are used to examine switching times. In addition, we give a different condition for bistability which results in a larger range of admissibleCvalues.

Marc Brunel, Cafer Özkul, Kamel Aı̈t-Ameur +1 more

David E. Grant, Harry J. Kimble

Hui Wang, Lan Wen-guang, Lin Wei-Zhu +2 more

Based on the established theory of photoinduced exciton bleaching of the polymers with nondegenerated ground state,we calculated the transient mirrorless optical bistability of photoexcitation and relaxation processes in the polymers.The results show that the transient saturation absorption mirrorless optical bistabilities and the increasing absorption mirrorless optical bistabilities can be obtained from the ultrafast excitation and relaxation processes in the polymers with nondegenerate ground state,and the switching time of the optical bistabilities is of the order of fs or ps.With the increase of the delay time of the probe pulse relative to pump pulse,the nature of mirrorless optical bistability can change from the saturation absorption optical bistability to increasing absorption optical bistability,and the rate of change is proportional to the speed of relaxation of the photoinduced exciton.