We present a simulation study of terahertz radiation from a gas driven by two-color laser pulses in a broad range of frequency ratios ω1/ω0. Our particle-in-cell simulation results show that there are three series with ω1/ω0=2n, n+1/2, n±1/3 (n is a positive integer) for high-efficiency and stable radiation generation. The radiation strength basically decreases with the increasing ω1 and scales linearly with the laser wavelength. These rules are broken when ω1/ω0<1 and much stronger radiation may be generated at any ω1/ω0. These results can be explained with a model based on gas ionization by two linear-superposition laser fields, rather than a multiwave mixing model

Accelerated degradation test by UV pulse laser and fluorescence tubes for ethylene vinyl acetate (EVA) used as encapsulation of PV-cells is compared. Samples of glass/EVA/glass are prepared and irradiated by a UV pulse laser at 355nm with a repetition rate of 10 Hz, 5 ns pulse width and 10 mJ pulse energy.Spot size is expanded to Ixl cm 2 and thus averaged energy