Measurement of positive gain on the 1315nm transition of atomic iodine pumped by O2(a1Δ) produced in an electric discharge

Abstract

Laser action at 1315 nm on the I͑ 2 P 1/2 ͒ → I͑ 2 P 3/2 ͒ transition of atomic iodine is conventionally obtained by a near-resonant energy transfer from O 2 ͑a 1 ⌬͒, which is produced using wet-solution chemistry. The system difficulties of chemically producing O 2 ͑a 1 ⌬͒ has motivated investigations into gas phase methods to produce O 2 ͑a 1 ⌬͒ using low-pressure electric discharges. In this letter we report on positive gain on the 1315 nm transition of atomic iodine where the O 2 ͑a 1 ⌬͒ was produced in a flowing electric discharge. The electric discharge was followed by a continuously flowing supersonic cavity that was necessary to lower the temperature of the flow and shift the equilibrium of atomic iodine more in favor of the I͑ 2 P 1/2 ͒ state. A tunable diode laser system capable of scanning the entire line shape of the (3,4) hyperfine transition of iodine provided the measurements of gain.

Observations of gain on the I(P1∕22→P3∕22) transition by energy transfer from O2(aΔg1) generated by a microwave discharge in a subsonic-flow reactor

“…5 In this letter, we report similar observations of positive I * → I gain in a subsonic microwave-discharge flow reactor near room temperature. 1,2 Gas-phase electrical generation of O 2 ͑a͒ offers potential for efficient, light-weight, closed-cycle laser systems.…”

“…As previously observed by Carroll et al, 5 addition of NO 2 reduces the absorption as ͓NO 2 ͔ added approaches ͓O͔ o , and the system approaches transparency. The I * emission intensity increases, signifying transfer of population from I to I * .…”

Production of O2(Δ1) in flowing plasmas using spiker-sustainer excitation

“…The long lifetime of O 2 ͑ 1 ⌬͒ ͑60 min͒ and robustness against quenching enables transport over long distances to the laser cavity. [10][11][12][13][14][15][16][17][18][19][20][21][22] Recently, positive gain was reported in atomic iodine resulting from electric discharge produced O 2 ͑ 1 ⌬͒, 23,24 followed by laser demonstrations. 8,9 Recent and ongoing investigations have shown that substantial yields of O 2 ͑ 1 ⌬͒ can be generated by an appropriately tailored electric discharge, typically in mixtures with rare gas diluents such as He.…”

Advanced Gas Laser Experiments and Modeling

“…The electrically driven oxygen-iodine laser (ElectricOIL) that was first demonstrated in 2005 [Carroll, 2004;Carroll, 2005] operates on the electronic transition of the iodine atom at 1315 nm, I( 2 P 1/2 ) → I( 2 P 3/2 ) [denoted hereafter as I * and I respectively]. The lasing state I * is produced by near resonant energy transfer with the singlet oxygen metastable O 2 (a 1 Δ) [denoted hereafter as O 2 (a)].…”