| 摘要 |
<p>PROBLEM TO BE SOLVED: To suppress parasitic oscillation by reducing optical losses in a direction in which a fundamental wave enters while making optical losses in an optical resonator different depending on the direction of propagation of light. SOLUTION: A 1/2 wavelength plate 10 is disposed within an optical resonator, and at least one polarization-dependent optical loss is given inside the optical resonator. In a laser beam generator 1, the plate 10 and the polarization- dependent optical loss are combined whereby optical losses codirectional with a fundamental wave incident from a laser beam source 2 can be decreased and those counter-directional to the fundamental wave are increased. Since the optical resonator is provided with the directional loss in the laser beam generator thus constructed, parasitic oscillation in the counterpropagating mode can be prevented, and hence stable oscillation can be obtained.</p> |
