| 摘要 |
PROBLEM TO BE SOLVED: To reduce average energy within a light emitting time by constituting plural optical paths so that they may have the specified difference of optical path length from each other and executing the pseudo prolongation of the emitting time of pulse light. SOLUTION: The pulse light emitted from a laser light source 1 is made incident on a half mirror 10 and divided into reflected light and transmitted light. The reflected light is made incident on a mirror 14. After the transmitted light is successively reflected by mirrors 11 to 13, it is made incident on the half mirror 10 again. A circulation optical path formed by three mirrors 11 to 13 and the half mirror 10 are set to have the specified optical path length, and functions as a means for giving the difference of the optical path length. The light component reflected at and after the second time by the half mirror 10 is gradually attenuated by an amount equal to the light transmitted through the half mirror 10 in every circulation, and finally all the light is transmitted through the half mirror 10. Therefore, the loss of light quantity is not caused in principle in the case the reflectance of the mirrors 11 to 13 is 100%, respectively. |
