LASER BEAM WAVELENGTH CONVERTER AND METHOD FOR THE SAME

摘要

PROBLEM TO BE SOLVED: To improve wavelength conversion efficiency and to lessen the damage by concentration of irradiation of a wavelength conversion element with a laser beam. SOLUTION: This laser beam wavelength converter has a wavelength conversion element 11 which consists of a lithium tetraboride single crystal and of which the laser beam incident surface is a face satisfying a phase matching condition of a type I (ooe), a pair of first and second concave mirrors 12 and 13 which face each other so as to put the element in-between, is disposed symmetrically with the center of the single crystal, reflect the laser beam of a basic wave and transmit the second harmonic laser beam of the basic wave by the element and a first total reflection mirror 14 which reflects the laser beam reflected by the second concave mirror so as to return the laser beam again to the second concave mirror in parallel with the laser beam.