Generation of Controllable High Energy Nanosecond Flat-Top Waveform Based on Brillouin Amplification

We propose a method based on Brillouin amplification, which reshapes the Gaussian pulse generated from a Q -switched laser into the flat-top waveform. The numerical simulations show that the reshaped waveform depends on Stokes pulse width and energy, and optimum conditions for a flat waveform are also investigated. It is demonstrated experimentally by the independent two-cell filled with FC-40 liquid. In the experiment, the flat-top waveform pulses with width from 9.1 to 13.3 ns and continuously adjustable energy from 90 to 210 mJ are obtained at the wavelength of 1064 nm. The pulses with flat-top waveform and high energy are achieved by injecting a small Stokes seed into the Brillouin amplifier, which is a novel method to obtain high-energy flat-top laser pulses.