Light bullets in spatially modulated Laguerre-Gauss optical lattices

We investigate the generation and stability of light bullets (LBs) in Laguerre-Gauss (LG) optical lattices, in which both linear and nonlinear changes in the refractive index are spatially modulated. We demonstrate that the linear and nonlinear contributions considerably affect the bullet shape and its range of stability; at the same time the nonlinear modulation depth, through the propagation constant, affects the width of the stability domain. We find that the energy of stable space-time solitons increases with the increase in the modulation depth. We discover that the behavior of LBs in LG optical lattices is substantially different from the behavior in the more familiar Bessel lattices.