| 摘要 |
1,147,850. Diode lasers; PN junction devices. TURLABOR A.G. 4 March, 1968 [7 March, 1967], No. 10421/68. Headings H1C and H1K. A PN junction diode laser has a portion 10b of surface 10, from which radiation is emitted, made opaque or diffusive. The object is to prevent rays 18 reflected in directions not parallel to the plane of the junction being transmitted through surface 10 and producing interference fringes in the far-field image by interference with beam 13. The crystal 1 may be of gallium arsenide with a tellurium-doped N-region and a zinc-doped P-region, and portion 10b may be roughened or covered with an opaque coating, or covered by a separate shield. Portion 10b should extend as close to the junction region 8 as is possible without disturbing output beam 13, a distance of 4Á being mentioned. If surface 9 is partially transmissive a similar opaque or diffusive portion may be provided thereon. It is stated that roughening of the surface 10a of the P- region is unnecessary when using gallium arsenide since light rays are strongly absorbed therein, but may be required with other materials. |
