Transient transverse stimulated Brillouin scattering with a broad-band pump

The threshold for stimulated Brillouin scattering (SBS), which can damage optical components and be an energy loss mechanism in high-power pulsed laser systems, can be increased by using a broadband laser or by segmenting the aperture in order to limit the interaction length. A theoretical model of transient broadband SBS is developed. The authors start by considering the case of transient SBS with a monochromatic pump and find the effective interaction length for a pump pulse of a given duration. Using this interaction length, they derive expressions for the threshold intensity and for the window size required to avoid SBS with a pulse of given power and duration. They compute the steady-state gain and threshold intensity as a function of bandwidth for a multimode laser with large mode spacing