Spectroscopic study of a moly-oxide electrodeless discharge for lighting applications

Summary form only given. Due to the hazardous material designation of spent fluorescent bulbs on board naval vessels, the Naval Research Laboratory has been investigating alternative lighting concepts which are free of mercury. The ideal goal is an efficient, large volume source, which provides white light directly without the use of a phosphor coating. A previous abstract (ICPOS '99) presented the initial report of a molybdenum-oxide plasma with potential applications for lighting. The experimental lamp consists of a cylindrical quartz tube filled with a flowing mixture of argon and oxygen at 1 Torr pressure, and an axial moly wire. The plasma is inductively driven by an exterior RF coil and produces 5500 lumens at 200 W. To the unaided eye the emission appears as white with a bluish tinge. The present research focuses on coil design and high resolution spectroscopy. With a stove top-like coaxial coil the network is well matched, parasitic discharges are eliminated, and the quartz above and below the coil remains clear. The quartz is hot enough to prevent condensation of MoO/sub x/ on the walls, suggesting the potential for a recycling mechanism. The presence and variation of atomic and molecular features with operating conditions, e.g., power, pressure, and composition, will be discussed in relation to the nature of the white light emission.