Abstract

With the advent of high power table top laser systems it has become possible in recent years to study the physics of free electrons interacting with ultra-intense laser fields. Of particular interest has been the possibility of generating high order harmonics by the process of nonlinear Thomson scattering. Although this problem has been studied theoretically for several decades,¹ experimental tests have been possible only recently. Initial signatures of relativistic harmonics were obtained in experiments that looked at the low order emission (2^nd and 3^rd) from underdense plasmas.^2,3 We present for the first time experimental signatures of this process in the high-order VUV emission from the plasma.

© 2002 Optical Society of America