Observation of three-half harmonic radiation from plasmas irradiated by a 0·26 μm wavelength laser

Time-integrated measurements have been made of three-half harmonic light energy emitted from 0·26 μm laser-produced plasmas. The main results are the experimental dependence of 3/2ω₀ conversion efficiency and threshold on electron density-profile shape. Various density profiles are achieved by irradiating different kinds of target; their shapes are estimated with the help of two-dimensional hydrodynamic simulations.