Microwave assisted laser-induced breakdown spectroscopy at ambient conditions

Jan Viljanen, Zhiwei Sun, Zeyad T. Alwahabi

    Research output: Contribution to journalArticleScientificpeer-review

    28 Citations (Scopus)

    Abstract

    Signal enhancements in laser-induced breakdown spectroscopy (LIBS) using external microwave power are demonstrated in ambient air. Pulsed microwave at 2.45 GHz and of 1 millisecond duration was delivered via a simple near field applicator (NFA), with which an external electric field is generated and coupled into laser induced plasma. The external microwave power can significantly increase the signal lifetime from a few microseconds to hundreds of microseconds, resulting in a great enhancement on LIBS signals with the use of a long integration time. The dependence of signal enhancement on laser energy and microwave power is experimentally assessed. With the assistance of microwave source, a significant enhancement of ∼ 100 was achieved at relatively low laser energy that is only slightly above the ablation threshold. A limit of detection (LOD) of 8.1 ppm was estimated for copper detection in Cu/Al2O3 solid samples. This LOD corresponds to a 93-fold improvement compared with conventional single-pulse LIBS. Additionally, in the microwave assisted LIBS, the self-reversal effect was greatly reduced, which is beneficial in measuring elements of high concentration. Temporal measurements have been performed and the results revealed the evolution of the emission process in microwave-enhanced LIBS. The optimal position of the NFA related to the ablation point has also been investigated.

    Original languageEnglish
    Pages (from-to)29-36
    Number of pages8
    JournalSpectrochimica Acta Part B: Atomic Spectroscopy
    Volume118
    DOIs
    Publication statusPublished - 1 Apr 2016
    Publication typeA1 Journal article-refereed

    Keywords

    • Copper Detection
    • Laser-induced breakdown spectroscopy
    • Microwave signal enhancement

    Publication forum classification

    • Publication forum level 1

    ASJC Scopus subject areas

    • Instrumentation
    • Atomic and Molecular Physics, and Optics
    • Analytical Chemistry
    • Spectroscopy

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