title: Optimally enhanced optical emission in laser-induced breakdown spectroscopy by combining spatial confinement and dual-pulse irradiation.
abstract: In laser-induced breakdown spectroscopy (LIBS), a pair of aluminum-plate walls were used to spatially confine the plasmas produced in air by a first laser pulse (KrF excimer laser) from chromium (Cr) targets with a second laser pulse (Nd:YAG laser at 532 nm, 360 mJ/pulse) introduced parallel to the sample surface to re-excite the plasmas. Optical emission enhancement was achieved by combing the spatial confinement and dual-pulse LIBS (DP-LIBS), and then optimized by adjusting the distance between the two walls and the interpulse delay time between both laser pulses. A significant enhancement factor of 168.6 for the emission intensity of the Cr lines was obtained at an excimer laser fluence of 5.6 J/cm(2) using the combined spatial confinement and DP-LIBS, as compared with an enhancement factor of 106.1 was obtained with DP-LIBS only. The enhancement mechanisms based on shock wave theory and reheating in DP-LIBS are discussed.
authors.affiliation: Wuhan National Laboratory for Optoelectronics (WNLO), College of Optoelectronics Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei, China.
authors.forename: L B
authors.initials: LB
authors.lastname: Guo
authors.forename: B Y
authors.initials: BY
authors.lastname: Zhang
authors.forename: X N
authors.initials: XN
authors.lastname: He
authors.forename: C M
authors.initials: CM
authors.lastname: Li
authors.forename: Y S
authors.initials: YS
authors.lastname: Zhou
authors.forename: T
authors.initials: T
authors.lastname: Wu
authors.forename: J B
authors.initials: JB
authors.lastname: Park
authors.forename: X Y
authors.initials: XY
authors.lastname: Zeng
authors.forename: Y F
authors.initials: YF
authors.lastname: Lu
mesh_terms: D000535:Aluminum / Q000737:chemistry; D002857:Chromium / Q000737:chemistry; D020378:Confined Spaces; D004867:Equipment Design; D005461:Fluorine / Q000737:chemistry; D007726:Krypton / Q000737:chemistry; D054018:Lasers, Excimer; D053844:Lasers, Solid-State; D013057:Spectrum Analysis / Q000295:instrumentation* / Q000379:methods*
chemical_list: D002857:Chromium; D005461:Fluorine; D007726:Krypton; D000535:Aluminum