General numerical method for characterizing multi-photon absorbing materials against high-intensity lasers
Within such a fast growing area, we are working on designing and implementing general numerical techniques which will significantly reduce a typically long development-manufacturing cycle of new nonlinear materials. The core of the current numerical model and software is a numerical solver of a coupled system of nonlinear PDEs which describes a propagation of an unguided electromagnetic field through the nonlinear materials. By using "basic absorption diagrams", we proposed a systematic way of describing all the materials which optical responses can be characterized by our solver. We call them "generic materials".
The main feature of the current model is that there are no restrictions on a type of the absorption which a given generic material exhibits. Our model allows attributing single- or multi-photon absorption/relaxation virtually to any energy level of the material's molecule. This makes possible to apply the same numerical algorithm for variety of generic materials which otherwise will require a specialized software for each particular nonlinear material.
The primal goal of this project is to better formalize the set of generic materials and to significantly extend the current mathematical model to encompass a majority of existing nonlinear materials which exhibit variety of different optical phenomena besides multi-photon absorption.
Current features of our theoretical model and software include:
- radially-dependent numerical solution of coupled system of rate-propagation equations which describes unguided electromagnetic field propagation through multi-photon absorbers;
- numerical scheme is stable within a large range of incident energy values, including moderate to high intensity lasers, and nanosecond to femtosecond regimes;
- it takes into account excited-state absorption, ESA;
- it operates on a wide range of multi-photon absorbers, including by not limited to two-photon absorbers, TPA, and three-photon absorbers, 3PA;
- complete time-resolved radial-dependent population density analysis;
- detailed analysis of contribution of every energy level to the total absorption;
E. Parilov, M. J. Potasek, " Generalized theoretical treatment and numerical method of time-resolved radially-dependent laser pulses interacting with multi-photon absorbers", (Journal of the Optical Society of America B, Vol. 23, No. 9, pp. 1894-1910, 09/2006)
