| 摘要 |
<p>A laser oscillator which is capable of preventing damage caused by light reflected from a workpiece and a decrease in productivity resulting therefrom. Between a rear mirror (2) and an output mirror (4) within the laser oscillator is arranged a bending mirror (3). The bending mirror (3) has a coating formed on the surface thereof, which reflects S-polarized light sufficiently but has a low reflectance with respect to P-polarized light. A laser beam (1) is amplified between the rear mirror (2) and the output mirror (4), and emitted out through the output mirror (4). The laser beam (1) output at this time is formed by an S-polarized light (la). The S-polarized light (1a) is converted to a circularly polarized light by a zero-shifting mirror (5) and a quarter wavelength mirror (6). The laser beam (1) converted to the circularly-polarized light turns in a perpendicular direction at a mirror (7) and is converged onto a workpiece (9) by a condenser lens (8). Part of the laser beam 1 irradiated onto the workpiece (9) is reflected therefrom and returns along the same path that the laser beam (1) has been emitted therethrough. This reflected light input via the output mirror (4) is formed by a P-polarized light (1b). The P-polarized light (1b) received back into the laser oscillator is attenuated when reflected from the bending mirror (3). <IMAGE></p> |
