Optimally enhanced optical emission in laser-induced breakdown spectroscopy by combining spatial confinement and dual-pulse irradiation

Authors

L. B. Guo, Huazhong University of Science and Technology, University of Nebraska-Lincoln
B. Y. Zhang, University of Nebraska-Lincoln
X. N. He, University of Nebraska-Lincoln
C. M. Li, Huazhong University of Science and Technology, University of Nebraska-Lincoln
Y. S. Zhou, University of Nebraska-LincolnFollow
T. Wu, Huazhong University of Science and Technology
J. B. Park, University of Nebraska-Lincoln,
X. Y. Zeng, Huazhong University of Science and Technology
Yongfeng Lu, University of Nebraska-LincolnFollow

Document Type

Article

Date of this Version

1-16-2012

Citation

Optics Express 20:2 (2012), pp. 1436 - 1443.

Comments

Copyright © 2012 Optical Society of America. Used by permission.

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/cm2 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.