| 摘要 |
PROBLEM TO BE SOLVED: To provide a wavelength converter which first reduces influences by changes in a spatial phase distribution on a laser beam having flat-top spatial distribution power, and then converts wavelengths.SOLUTION: A wavelength converter 20 includes: an input port where a single-mode laser beam is input; a beam homogenizer 52 that receives an input of the single-mode laser beam from the input port and outputs light with a flat-top distribution of light intensity; a wavefront aberration compensation element 6 that smooths phases of the laser beam from the beam homogenizer 52 and outputs the beam; and a wavelength conversion element 7 comprising a nonlinear optical crystal that receives the laser beam from the beam homogenizer 52 and outputs light having a wavelength different from that of the input light, as a laser beam with a flat-top distribution of light intensity. The beam homogenizer 52 gives a beam waist at a position different from a position where the flat-top distribution of light intensity is present. The wavelength converter includes the wavefront aberration compensator 6 that aligns phases of the laser beam from the beam homogenizer 52 and outputs the light as parallel beams to the wavelength conversion element 7. Thus, the wavelength converter converts wavelengths of a laser beam and outputs the laser beam. |
