LASERS IN INDIRECT-BANDGAP SEMICONDUCTIVE CRYSTALS DOPED WITH ISOELECTRONIC TRAPS

摘要

There are disclosed lasers in indirect-bandgap semiconductive crystals, such as gallium phosphide crystals containing isoelectronic traps such as those provided by nitrogen or bismuth, in which low-threshold, high-gain stimulated emission of coherent radiation is obtained. It was previously believed that stimulated emission in indirect-bandgap materials was unlikely. In contrast to similarly-composed electroluminescent devices, such a laser typically has an optical resonator provided along the junction plane. An experimental embodiment is a superradiant laser that is optically pumped by coherent light along a line extending to an edge of the crystal.