Lasing without inversion in a polymer optical nonlinear system
Tingwan Wu, Yunjun Yu, Wenbo Huang
This paper studies the characteristics of the nonlinear optical system in a model, which may be considered as that containing conjugate polymer, such as polydiacetylense. The dynamic equations are established through the approach of density matrix elements. The parameter conditions of laser and lasing without inversion (LWI) are discussed and the thresholds of pumping and probing fields to produce LWI are determined. The nonlinear susceptibility of the system is deduced from the density matrix equations and the forced oscillation model of laser and bistability is used to study the bi- or multi-stability of the system under lasing, or inversion without lasing (IWL) and LWI conditions. The results indicate that to realize OB or OM output in IWL or LWI situation, there must be some additional conditions on the relaxation and transition rates, also the critical output light intensity. Finally, theoretical analysis and numerical computing show that there exists unstable critical point of second kind phase transition, in such tri-stable state.
Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Jun 15, 2001•0 citations