Developing mobile LIBS solutions for real world applications

Abstract

We present a new type of handheld laser-induced breakdown spectroscopy (LIBS) spectrometer for developing mobile atomic spectroscopy solutions for real world applications. A micro diode-pumped passive Q-switched solid-state laser with high repetition rate of well above 1 kHz in comparison to 1-10 Hz as used in a traditional LIBS instrument is employed to produce a train of laser pulses. The laser beam is further fast scanned over a pre-defined area, hence generating several hundreds of micro-plasmas per second at different locations. Synchronized miniature CCD array spectrometer modules collect the LIBS signal and generate LIBS spectra. By adjusting the integration time of the spectrometer to cover a plurality of periods of the laser pulse train, the spectrometer integrates the LIBS signal produced by this plurality of laser pulses. Hence the intensity of the obtained LIBS spectrum can be greatly improved to increase the signal-to-noise ratio (SNR). This unique feature of the high repetition rate laser based LIBS system allows it to measure elements at trace levels, hence reducing the limit of detection (LOD). The increased signal intensity also lessens the sensitivity requirement for the optical spectrometer. In addition, the energy of the individual laser pulse can be reduced in comparison to traditional LIBS system to obtain the same signal level, making the laser pulse less invasive to the sample. The typical measurement time is within 1 second. Several examples of real world applications will be presented.