@article{4138, author = {A. Maznev and F. Bencivenga and A. Cannizzo and F. Capotondi and R. Cucini and R. Duncan and Thomas Feurer and Travis Frazer and L. Foglia and H.-M. Frey and Henry Kapteyn and Joshua Knobloch and G. Knopp and Claudio Masciovecchio and R. Mincigrucci and G. Monaco and Margaret Murnane and I. Nikolov and E. Pedersoli and A. Simoncig and A. Vega-Flick and K. Nelson}, title = {Generation of coherent phonons by coherent extreme ultraviolet radiation in a transient grating experiment}, abstract = {We investigate the excitation of coherent acoustic and optical phonons by ultrashort extreme ultraviolet (EUV) pulses produced by a free electron laser. Two crossed femtosecond EUV (wavelength 12.7 nm) pulses are used to excite coherent phonons at a wavelength of 280 nm, which are detected via diffraction of an optical probe beam. Longitudinal and surface acoustic waves are measured in BK-7 glass, diamond, and Bi4Ge3O12; in the latter material, the excitation of a coherent optical phonon mode is also observed. We discuss probing different acoustic modes in reflection and transmission geometries and frequency mixing of surface and bulk acoustic waves in the signal. The use of extreme ultraviolet radiation will allow the creation of tunable GHz to THz acoustic sources in any material without the need to fabricate transducer structures.}, year = {2018}, journal = {Applied Physics Letters}, volume = {113}, pages = {221905}, month = {2018-11}, issn = {0003-6951}, url = {https://aip.scitation.org/doi/full/10.1063/1.5048023}, doi = {10.1063/1.5048023}, }