Generation of acoustic waves by an extreme ultra violet free electron laser in a transient grating experiment

The use of lasers to generate acoustic waves revolutionized the field of ultrasound and enabled numerous key developments in both fundamental research and applications. In the past decade, remarkable progress has been achieved in developing coherent sources of radiation operating in the extreme ultraviolet (EUV) and x-ray ranges, such as free electron lasers, which already yielded many breakthroughs in different fields of science. We expect that the field of ultrasonics will also greatly benefit from the availability of coherent EUV and x-ray sources. So far, a number of studies explored the use of coherent EUV and x-ray radiation for detection of acoustic waves. In this report, we describe the first experiment on the generation of surface and bulk acoustic waves in the tens of GHz range by EUV light.