  Detailed two dimensional particle-in-cell (PIC) simulations and numerical
calculations of electron density profiles, based on a simplified model, were
performed to show for the first time that underdense plasma, induced by two
pairs of counterpropagating femtosecond-laser pulses in a gas, could be
manipulated by ponderomotive-optical lattices to form periodic structures.
These novel phenomena facilitate the localization and enhancement of the
generating laser pulse intensities by the self-induced plasma photonic lattices
(PPLs) and exhibit unique spatiotemporal dynamics. Variation of the initial
plasma density profile and the configuration of the interacting pulses enabled
control over the attainable PPL structures. It is predicted that by using a
non-uniform initial plasma density, light emission in a preferred direction
could be obtained.
