Optical wavelength conversion device and method for manufacturing the same

A method for manufacturing an optical wavelength conversion device, comprising:

• a preparing step of preparing a main body made of an amorphous material;
• a first irradiating step of irradiating the main body with a first laser beam focused on a surface of or inside the main body and exciting electrons in a focus region of the first laser beam, the first laser beam being a femtosecond laser beam having a wavelength outside an absorption wavelength band of the main body;
• a second irradiating step of irradiating the main body with a second laser beam focused to overlap the focus region of the first laser beam and heating the focus region of the first laser beam, the second laser beam being a continuous wave laser beam or a pulsed laser beam with a pulse width of one picosecond or more, the second laser beam being a laser beam having, outside the focus region of the first laser beam, a wavelength outside the absorption wavelength band of the main body;
• and
• a scanning step of varying a relative position of the main body and an overlapping focus region of the first and second laser beams while the first and second irradiating steps are being intermittently carried out in a synchronized manner.