| 摘要 |
1485912 Semi-conductor lasers MAXPLANCK-GES ZUR FORDERUNG DER WISSENSCHAFTEN EV 21 March 1975 [25 March 1974] 11886/75 Headings H1C and H1K [Also in Division C4] A laser comprises an optically pumped fibre or thin layer of an ultraphosphate, and particularly NdP 5 O 14 , the pumping radiation being directed orthogonally to the fibre axis or the surface of the thin layer. Sun-pumped fibre or thin layer : sun light is directed by a mirror 10, Fig. 1, and focusing cylindrical lens 12 on to a laser active body of NdP 5 O 14 which is mounted on a transparent substrate 18 backed by a solar cell 16. The cell may be subdivided and used for automatic tracking. Pumping by glow discharge or tungsten lamps: a pump lamp 22, Fig. 2a, and a laser active fibre are positioned in a reflector in the form of an elliptic cylinder, the lamp being either a capillary glow discharge unit or a straight or stretched coil of tungsten wire. Pumping by non-coherent light emitting diode. A laser active fibre 36, Fig. 3a, or a thin laser active layer, Fig. 3b (not shown) is positioned adjacent a P-N junction 34 in a GaAPAs semi-conductor structure 32, the diode being mounted on a heat sink 30 and having a stripe electrode 38 formed by a diffused gold layer partially isolated by an oxide layer 39. Plural active media in a monolithic semiconductor pumping structure: in Fig. 4a laser active fibres 40 are located by optical cement 47 in spaced grooves etched in a semi-conductor structure comprising a GaAs layer 42, an N-type GaAPAs region 43 and a P-type region 44 formed by diffusion. A discrete P-N junction from which non-coherent pumping light is emitted vertically from the junction is provided for each fibre, the pumping radiation applied to each fibre being individually controlled through respective stripe electrodes 48. In a modification, Fig. 4b, the laser active media are thin layers 41 carried by a substrate 46 and covered by a glass layer 50. This assembly is secured to the semi-conductor structure by optical cement 47. The field concentration within the semiconductor may be increased by zinc or gold inserts 49. Pumping semi-conductor structure in the form of a reflecting ellipsoid cylinder: the semiconductor structure is formed by combining two half cylinders 60, 80 of GaAPAs, Fig. 5b, grooves being provided at the ellipsoid foci for respectively accommodating a laser active fibre or thin layer 62 and a conduction wire 86 for the semi-conductor excitation current. A gold electrode layer 68, 84 is included in the conduction wire groove which is encircled by a P-type region 66 and a P-N junction 64, 82. The outer face of the cylinder is polished and covered by a reflective layer 70 so as to focus light emitted by the P-N junctions on to the laser active fibre or layer.
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