| 摘要 |
PURPOSE:To sharply increase the laser gain part of an excited solid-state laser medium by providing a diffraction grating which makes the light emitted from a laser to incident to the solid-state laser medium after diffracting the light to the direction in which a laser resonator mode is formed. CONSTITUTION:Zero-th order diffracted light 29 is propagated through a solid-state laser medium 22 while the light 29 is subject to such absorption that the intensity of the light is exponentially attenuated in a direction nearly perpendicular to the optical axis 6 and forms an excitation area. First-order light 30 advances in the direction at an angle (=0 deg.) expressed by the formula from the normal of a diffraction grating 24. The pitch (d) of the grating 24 is set so that the angle theta can approach 90 deg.. When the pitch (d) is set in such way, the diffracted light 30 is reflected by a plane 25 after the light 30 is propagated through the medium 22 while the light 30 is subject to such absorption that the intensity of the light 30 is exponentially attenuated in a direction almost parallel to the optical axis 6 and is again propagated through the medium 22, with the light 30 again being subject to the same absorption. Finally, the light 30 forms the excitation area. Then first-order diffracted light 31 advances in a direction which is almost symmetrical to the direction of the light 30 about the normal of the grating 24 and forms the excitation area after the light 31 is propagated through the medium 22, reflected by a plane 26, and again propagated through the medium 22. |
