| 摘要 |
A light source (100) generates multimode laser light. A wavelength conversion unit (200) converts the wavelength of the laser light generated by the light source (100). The wavelength conversion unit (200) is provided with a ferroelectric crystal. The ferroelectric crystal has a polarization reversal structure formed therein. The polarization reversal structure has a plurality of areas having different polarization reversal periods. The polarization reversal period in a first area satisfies the requirement for generating the second harmonic of the zero-order mode light of the laser light. The polarization reversal periods in the other areas satisfy the requirements for generating light having the same wavelength as the second harmonic of the zero-order mode light through the frequency summing of the +m order mode light and the -m order mode light of the laser light. |
