title: Amplification properties of vacuum ultraviolet Ar*2 produced by infrared high-intensity laser.
abstract: We report optical amplification of Ar(2)* at 126 nm, pumped by optical-field-induced ionization (OFI) created by an infrared high-intensity laser. A gain-length product of 0.84 was obtained by using multipass amplification with a vacuum ultraviolet (VUV) cavity. The gain-length product was increased up to 4.3 through the use of single-pass amplification with a VUV reflector and a hollow 5.0 cm-long fiber. Similar small signal gain coefficients of 0.84 and 0.86 cm(-1) were obtained in two different experiments, in which OFI Ar plasma gain media were produced in free space filled with Ar and inside an Ar-filled hollow fiber.
authors.affiliation: Department of Electrical and Electronic Engineering and Photon Science Center, University of Miyazaki, Gakuen Kibanadai Nishi 1-1, Miyazaki 889-2192, Japan. kaku@opt.miyazaki‑u.ac.jp
authors.forename: Masanori
authors.initials: M
authors.lastname: Kaku
authors.forename: Shinya
authors.initials: S
authors.lastname: Harano
authors.forename: Ryota
authors.initials: R
authors.lastname: Matsumoto
authors.forename: Masahito
authors.initials: M
authors.lastname: Katto
authors.forename: Shoichi
authors.initials: S
authors.lastname: Kubodera