| 摘要 |
PURPOSE:To contrive to improve a wavelength conversion efficiency by reducing unabsorbed excitation light entering a non-linear optical material through providing a pinhole in an optical path ranging from a condensing lens to said non- linear optical material. CONSTITUTION:A throttle plate 25 and a non-linear optical material 17 are successively arranged on the injection side of the laser excited light 22 of a laser medium 15, and the smallest possible pinhole 27 of a diameter causing no loss to a laser cavity mode coinciding with the optical axis of the laser excited light 22 is formed on the diaphragm 25. Because excitation light 21 converges into a focus in the laser medium 15 by a condensing lens 13, unabsorbed excitation light 21 not absorbed by the laser medium 15 spreads rapidly when injected from the laser medium 15. Most of the unabsorbed excitation light 21 is intercepted when the excitation light 21 passes the pinhole 27 of the diaphragm 25. Therefore, the light 21 can be prevented from being injected into the non-linear optical material 17 and the temperature rise of the material 17 under the influence of the light 21 is suppressed so that it is possible to optimize phase matching conditions to realize a stable wavelength conversion. |
