Abstract: A laser device includes, within an envelope, an electron gun, and a structure providing a light resonating cavity which includes confronting reflecting surfaces and a semiconductor material which is pumped by the electron beam producing emission of light within the cavity. The resonator cavity consists of mirror bodies having confronting reflective surfaces in parallel planes, one surface being fully reflective and one surface being partially reflective, and a semiconductor wafer mounted adjacent to one of the mirror bodies to be impinged by the electron beam. The electron beam is swept across the semiconductor wafer in a selected pattern, such as the conventional television pattern, and a laser beam is emitted from the lasering device which follows the pattern traced by the electron beam. The apparatus may be controlled by a television produced signal.

Abstract: For illuminating an area of a structure which is prone to explosion due to dust or vapors in the atmosphere, a system includes fluorescent type lighting devices which are energized by radio frequency energy without any physical connection to the lighting devices. The lighting devices include sealed envelopes having fluorescent material on the inner wall surfaces, and containing a gas which responds to external radio frequency electromagnetic radiation to excite the fluorescent material and produce visible light. The lighting devices are mounted within the structure by insulating brackets and may be mounted within impact resistant protective enclosures. The lighting devices are energized by radiating devices of electromagnetic energy which are mounted adjacent to the several lighting devices within the explosion prone area, and which are supplied with radio frequency electromagnetic energy through appropriate means from a generating source remote from or outside of the explosion prone area.