Effect of a thin optical Kerr medium on a Laguerre-Gaussian beam

Using a generalized Gaussian beam decomposition method the authors determine the propagation of a Laguerre-Gaussian (LG) beam that has passed through a thin nonlinear optical Kerr medium. The orbital angular momentum per photon of the beam is found to be conserved while the component beams change. As an illustration of applications, the authors propose and demonstrate a Z-scan experiment using a LG01 beam and a dye-doped polymer film.