Measurements of laser-speckle-induced perturbations in laser-driven foils

We have measured modulations imprinted by laser speckle in laser-driven ${\mathrm{CH}}_2$ foils at ${10}^{14}$ W/${\mathrm{cm}}^2$ (laser wavelength 0.53 μm). We have calibrated the amplitude and Rayleigh-Taylor growth of these modulations with single-mode surface perturbations, converting the imprint to an equivalent surface finish. We examined this imprint for a static speckle pattern and with two different bandwidths on the drive laser. The addition of bandwidth and dispersion to the drive laser reduced the imprinted modulations, with the highest bandwidth showing the largest reduction in imprint, in agreement with L A S N E X simulations. © 1996 The American Physical Society.