Transverse Propagation Characteristics and Coherent Effect of Gaussian Beams

As an important electromagnetic field in experiment, Gaussian beams have non-vanishing longitudinal electric and magnetic components that generate significant energy fluxes on transverse directions. We focus on the transverse energy flux and derive the theoretical propagation properties. Unlike the longitudinal energy flux, the transverse energy flux has many unique physical behaviors, such as the odd symmetry on propagation, slower decay rate on resonant condition. By means of the characteristics of transverse energy flux, it is feasible to find the suitable regions where the information of coherent lights could be extracted exactly. With the typical laser parameters, we simulate the energy fluxes on receiver surface and analyze the corresponding distribution for the coherent light beams. Especially for coherent lights, the transverse energy flux on the y–z plane with x=0 and x–z plane with y=0, contains pure coherent information. Meanwhile, in the transverse distance |y| < 2W_0 (W_0 is the waist radius) and |x| < W_0/3 the coherent information could also be extracted appropriately.