| 摘要 |
PROBLEM TO BE SOLVED: To suppress the expansion of the spectrum band and the time- depending intensity modulation, by providing a first polarization control means for paralleling the polarizing direction of a laser beam passing through an exciting region to the optical path of an exciting light, and a second polarization control means for making the polarizing direction vertical. SOLUTION: A first polarization control means 2 is provided for paralleling the polarizing direction of a laser beam firstly passing through an exciting region 8 to the optical path of an exciting light P, and a second polarization control means 3 is provided for making vertical the polarizing direction of a large beam secondly passing through the exciting region 8 to the optical path of the exciting light P. In this constitution, the polarizing direction in firstly passing through the exciting region 8 is orthogonal to that in secondly passing through this region 8, this preventing the spatial hole burning due to the interaction of a first path P1 in firstly passing through the exciting region 8 with a second path P2 in secondly passing through the exciting region 8. Thus, the expansion of the spectrum band and time-depending intensity modulation can be suppressed. |
