Pulse-periodic chemical oxygen-iodine laser with active medium formation by volumetric electric discharge

Abstract

ABSTRACT The paper describes a study of pulse-periodic operation of a chemical oxygen-iodine laser. The generator in use was of the jet type with high chlorine utilization degree (• 97%). Atomic iodine was released by dissociating methyl-iodide ( KG 3 I) in volumetric electric discharge. Steady lasing was achieved at a repetition rate up to 30 Hz. The emission energy attained per individual pulse in a train was 1.1 J at a pulse energy repeatability of (3÷ 5) % and a specific energy extraction from the active medium of 1.7 J/L. The lasing pulse duration depended on the concentra-tion of methyl-iodide and the energy deposited into discharge. The minimal half-height duration of pulses was achieved as 10 µ m at a concentration of atomic iodine in the laser cavity ~1*10 15 cm -3 . Key words: chemical oxygen-iodine laser, pulse-periodic, methyl-iodide, volumetric electric discharge The pulse-periodic chemical oxygen-iodine laser (COIL) is considered by us as a likely applicant to technologies requiring the conditions that are unattainable so far with the aid of solid-state pulse-periodic lasers. It means the range of average lasing power from 1 to 10 kW at a per-pulse lasing energy up to 10 J. There are at least two approaches possible to get COIL in pulse-periodic mode of operation. The first consists of Q-switching in the laser cavity or gain modulation in the active medium. Along with this, the active medium is produced by mixing singlet oxygen with molecular iodine just as it takes place in cw lasing case. Application of this method to formation of large-volume active media has well-known restrictions applied to relaxation processes occurred during the interaction between singlet oxygen and iodine and we’d not describe it here. Another method proposed by scientists of the Lebedev Institution and confirmed by specialists in China assumes using an initially stable mix of singlet oxygen and iodine dissociating by one or another method upon filling the laser cavity by appropriate gases [1, 2, 3].