A new method for generation of ultrashort light bullets in bulk dispersive Kerr medium

Abstract

We propose a new method for ultrashort light pulse generation. This method is based on the spatiotemporal instability in dispersive Kerr medium. By formulating a linear instability analysis based on the (3+1)-dimensional nonlinear Schrodinger equation including arbitrary higher-order dispersions, we have disclosed the generic role played by arbitrary higher-order dispersions in spatiotemporal instability. We find that the fourth-order dispersion leads to the appearance of new instability regions which can extend far away from the original instability region. In addition, due to the fourth-order dispersion, temporal instability can develop for any spatial frequencies, and by increasing the spatial frequency, the corresponding temporal instability frequency can be easily increased. Numerical simulations show that the new instability regions can be used to generate a sequence of ultrashort light bullets. The repetition-rate of the generated bullets can be made quite large by increasing the corresponding spatial modulation frequency locating in the new instability region resulted from the fourth-order dispersion.