| 摘要 |
PROBLEM TO BE SOLVED: To obtain a wavelength conversion element which has reduced speckles and emits laser beams of large output.SOLUTION: The wavelength conversion element includes: a periodic polarization inversion structure on a non-linear optical substrate; and an electrode configured to apply a different electrical field for every region with a different polarization direction. When a voltage is applied to the electrode, the refractive index of a polarization inversion portion changes by the electrical field and the phase matching wavelength changes. By applying the voltage changing at high speed, the wavelength of second higher harmonics meeting the phase matching wavelength changes at high speed, and a high despeckle effect can be obtained. |
