Cryogenic CO laser excited by a photoionization discharge

Carbon monoxide was made to lase by exciting a dense N = 1.35 × 10¹⁹ cm ^{– 3} CO–N₂–He–(O₂–C₂H₄), gas mixture cooled to T = 110 K. A photoionization discharge was initiated by λ ≤ 130-nm ultraviolet radiation pulses of t ≈ 1 μs duration. The energy consumed in the photoionization process was 30% of that deposited in the volume discharge. The photoionization pump parameters were optimized and a study was made of the dynamics of reestablishing the optical homogeneity of the active medium after the photoionization and discharge pulses. Methods were proposed for raising the energy efficiency of CO photoionization lasers. A photoionization laser with an efficiency of ~11% and a specific output energy of 12 J · liter ^{– 1} · atm ^{– 1} was constructed. The laser pulse duration was 2–600 μs, depending on the gaseous composition of the medium. The absence of helium from the mixture caused a negligible deterioration in the laser energy characteristics.