Generation of 340-nm light by frequency doubling of a laser diode in bulk periodically poled LiTaO_3

Frequency doubling of a 680-nm laser diode in periodically poled LiTaO(3) is presented. By selective proton exchange followed by high-voltage pulse application, a second-order periodic domain inversion having uniform periodicity and optimum duty cycle was fabricated over a 10-mm interaction length in a 200-microm-thick LiTaO(3) substrate. A 340-nm wavelength of harmonic ultraviolet light was generated in a single pass through the domain-inverted structure.