The theory of propagation of partially coherent light is well known, but performing numerical calculations still presents a difficulty because of the dimensionality of the problem. We propose using a recently introduced method based on the use of elementary functions [Wald et al. Proc. SPIE6040, 59621G (2005)] to reduce the integrals to two dimensions. We formalize the method, describe its inherent assumptions and approximations, and introduce a sampling criterion for adequate interpolation. We present an analysis of some special cases, such as the Gaussian Schell-model beam, and briefly discuss generalized numerical propagation of two-dimensional field distributions.
A theoretical description of the propagation of an initially Gaussian beam through a “generalized” thin nonlinear medium is developed, where the linear part of the optical system can be characterized by an ABCD matrix. The optical field is determined on the output interface of the medium and is decomposed into Gaussian-Laguerre modes. These modes are then propagated through the optical system using the ABCD law, so that the field distribution at any point can be determined. We obtain an expression for the on-axis relative transmissivity of the combined system, which is valid for nonlinear absorption regimes to all orders of nonlinearity. The positions of the turning points of the normalized axial transmissivity as a function of the position of the medium are derived analytically to the first-order of nonlinearity. It is shown that, from measurements of these positions, the nonlinear refractive and absorptive strengths as well as the type of nonlinearity can be extracted.
The potential of InSb as a material for limiters for CO 2 laser pulses is explored. A model of the nonlinearity is presented and material parameters estimated from Z-Scans and ring-scans. This is then used to model the performance of a basic thin-sample defocussing limiter and find optimum conditions. A simple practical device for removing the gain switched peak from a TEA laser pulse is also described.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.