title: Observation of vacuum-ultraviolet Ar2* radiation gain at 126 nm produced by an ultrashort high-intensity laser pulse propagating in a hollow fiber.
abstract: We observed a small-signal gain of Ar2* emission at 126 nm by use of a hollow fiber to guide the high-intensity laser propagation in high-pressure Ar. The small-signal gain coefficient was measured to be 0.05 cm(-1) at 126 nm. Kinetic analysis revealed that the electrons produced by the high-intensity laser through an optical-field-induced ionization process initiated the Ar2* production processes. The increase in the emission intensity was measured to be exp(2.5), with an increase in the fiber length.
authors.affiliation: Department of Electrical and Electronic Engineering, Photon Science Center, Miyazaki University, Gakuen Kibanadai Nishi 1-1, Miyazaki 889-2192, Japan.
authors.forename: Masanori
authors.initials: M
authors.lastname: Kaku
authors.forename: Takeshi
authors.initials: T
authors.lastname: Higashiguchi
authors.forename: Shoichi
authors.initials: S
authors.lastname: Kubodera
authors.forename: Wataru
authors.initials: W
authors.lastname: Sasaki