WAVELENGTH CONVERSION ELEMENT, WAVELENGTH CONVERSION METHOD, PHASE MATCHING METHOD, AND LIGHT SOURCE DEVICE

摘要

Provided is a wavelength conversion element including a nonlinear optical crystal using a monocrystal. The nonlinear optical crystal has: a plurality of first regions having a predetermined polarity direction; a plurality of second regions having a polarity direction opposite to the predetermined direction; an incident plane into which a basic incident wave having a wavelength λ and a frequency ω comes in a substantially vertical direction with respect to the predetermined direction; and an outgoing plane from which a second harmonic having a frequency 2ω generated in the crystal goes out. The plurality of the first and the second regions are alternately formed with a cycle substantially identical to 'd' expressed by a predetermined expression.