| 摘要 |
<p>PROBLEM TO BE SOLVED: To compensate a walk-off angle, to improve the efficiency of wavelength coversion without shortening effective crystal length and to reduce the beam formation of projected light or eliminate its necessity. SOLUTION: The wavelength conversion element consists of a non-linear optical monocrystal for converting the wavelength of laser light 11. A twinning plane 14 for crossing the monocrystal exists on a position which is almost a half of the effective length of the monocrystal. It is preferable that a non- linear optical monocrystal is a twin lithium tetraboride 10 having a twinning plane 14 in which the non-linear optical monocrystal is a (112) plane, and in the case of incident light whose wavelength is 532 nm, it is preferable that a straight line 12 in the monocrystal obtained by extending the optical path of laser incident light 11 has an inclinationθm=63 deg.±1 deg. from the axis (c) of the monocrystal 10.</p> |
