| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a wavelength conversion device and method for making a high-efficiency wavelength conversion in comparison with a conventional wavelength conversion method, by the constitution of a simple device constituted using an optical system, which is generally available commercially. SOLUTION: A wavelength of a fundamental wave laser beam is converted into the wavelength of second harmonics in a nonlinear crystal 14. At that time, the fundamental wave laser beam not converted its wavelength is separated by a separator 16 to return to a polarizer 12 via a mirror 18 and the like, is made incident again on the crystal 14 and the wavelength of the laser beam is again converted into the wavelength of the second harmonics. That is, the laser beam converting its wavelength and the laser beam not converting its wavelength in the crystal 14 are separated from each other, the laser beam not converting its wavelength is combined with an incident laser beam to make incident again on the same crystal 14 and the laser beam reconverts its wavelength. Accordingly, it becomes possible to increase the wavelength conversion efficiency of the fundamental wave laser beam.</p> |
