Transient grating measurement of surface acoustic waves in thin metal films with extreme ultraviolet radiation

The authors demonstrate the use of coherent extreme ultraviolet (EUV) light in laser induced transient grating spectroscopy. In this work, the authors study the dispersion of pulsed laser induced surface acoustic waves in a thin uniform nickel film by monitoring the diffraction of 30 nm EUV light from the surface. Transient deformation of the sample surface leads to absolute diffracted intensities approaching 10^-3 for 1 Å displacement, an ∼700-fold increase in sensitivity compared with optical probing. EUV probing provides a convenient geometry for observing short wavelength acoustic propagation.