Generation of tunable coherent extreme-ultraviolet radiation at wavelengths as low as 66 nm by resonant four-wave mixing

Abstract

Tunable coherent extreme-ultraviolet (XUV) radiation at wavelengths as low as 66.86 nm was generated by two-photon resonant four-wave mixing in a hydrogen molecular gas jet. In this investigation, an ArF excimer laser was tuned to the E,F(1)Sigma(+)(g)(upsilon' = 6)-X(1)Sigma(+)(g)(upsilon' = 0) Q(1) transition of H(2), and the second-harmonic radiation of a dye laser was mixed to obtain the resultant XUV radiation. To our knowledge, this tunable XUV radiation is the shortest wavelength obtained so far by two-photon resonant four-wave mixing.