Wavelength converting element and wavelength converting laser apparatus

A wavelength converting laser apparatus comprising:

• a waveguide-type solid laser element that oscillates a fundamental wave laser beam;
• and
• a wavelength converting element that is of a planar waveguide type, includes a plate-like nonlinear optical material, and performs a wavelength conversion on a fundamental wave of a laser beam by propagating the fundamental wave in a plurality of laser oscillation modes in a direction perpendicular to a main surface of the plate-like nonlinear optical material, the direction being perpendicular to an optical axis, wherein
• periods of polarization inversions of the nonlinear optical material are changed so that each of the periods has a phase matching bandwidth that includes phase matching conditions of at least two of the plurality of laser oscillation modes and so that a non-polarization-inversion region and a polarization inversion region are formed in the nonlinear optical material.