Spatiotemporal smoothing of a laser beam employing a dynamic plasma phase plate

The spatiotemporal smoothing of the intensity distribution of a focused laser beam was investigated on the Iskra-4 laser setup using a dynamic plasma phase plate produced by vaporisation of a special target placed at the beginning of the caustic of the focused beam. It is shown that the transmittance of the plasma target in the 10¹³– 2 × 10¹⁴ W cm^-2 intensity range is no less than 70% – 80%. The introduction of the dynamic plasma phase plate lowered the relative fluctuations of the spatial intensity distribution from 100% to ~10%. The characteristic time of the intensity distribution variation in the focal plane is 0.4 ps.