| 摘要 |
PURPOSE:To make a single mode oscillation at a desired frequency by dispersing with a prism the radiated beam of single model semiconductor laser and by selectively feeding back the frequency to the laser. CONSTITUTION:There exists a spectrum 2 of radiating light other than the oscillating light around line spectrum 1 when the light is oscillating at a characteristic wave length lambda0. A single mode of oscillation at lambda is obtained if a light of a wave length lambda, other than lambda0 in an optical system having a wave length selecting property with a small loss, is fed back. When a line of diffraction grid and a normal on a plain mirror coincide and the laser beam 4 is changed to a parallel beam by a collimater and strikes along the plain 8 including grid line and at an angle (a) made by the grid normal N and a plain including the center of grid, the normal and the direction of dispersion, lambda=2mdcosphi sinalpha is selective fed back and the feed back image becomes an erected image increasing feed back effect, as if a feed back loss is decreased, and the oscillation at the wave length lambda is obtained. |
