Genta Masada

0.43 J, 10 Hz Fourth Harmonic Generation of Nd:YAG Laser Using Large Li2B4O7 Crystals

Using large-sized Li2B4O7 crystals, 0.43 J, 266 nm pulses are obtained from a 10 Hz Nd:YAG laser with a total conversion efficiency of 30.5%. Moreover, 4 W operation for over 15 h is demonstrated.

Reduction of Nonlinear Absorption in Li2B4O7 by Temperature- and Repetition Rate-Control

We address the critical issue of thermal dephasing of the UV harmonic generation process due to nonlinear absorption in Li2B4O7 crystals. Reduction of nonlinear absorption is achieved by increasing the crystal temperature up to 200 °C and reducing the pulse repetition rate. Our results show the way for significant improvement of the conversion efficiency for the fourth harmonic generation of Nd lasers using Li2B4O7 crystals.

0.43-J, 10-Hz fourth harmonic generation of Nd:YAG laser using large Li2B4O7 crystals

Using large-sized Li2B4O7 crystals, 0.43-J, 266-nm pulses are obtained from a 10-Hz Nd: YAG laser with a total conversion efficiency of 30.5 %. Moreover, long-term stable, 4-W operation over 15 hour is demonstrated.

Generation of 0.336-J, 10-Hz, 266-nm pulses from Nd:YAG laser using large Li/sub 2/B/sub 4/O/sub 7/ nonlinear crystals

Summary form only given. We have confirmed the long-term stability of the fourth harmonic generation of a Nd:YAG laser by use of Li/sub 2/B/sub 4/O/sub 7/ crystals with a cascade scheme. We report 336-mJ, 266-nm pulse generation from a 10-Hz, Q-switched Nd:YAG laser with a total conversion efficiency of 23%, and the long-term stability of over 5 hour. This performance is sufficiently good for the pump source of the TW-class UV femtosecond laser system. Additionally this high pulse energy UV laser is attractive for the substitution of the most of industrial KrF excimer lasers used for annealing applications.