High-Resolution High-Speed LIBS Microscopy

Abstract

Laser-induced breakdown spectroscopy (LIBS) imaging instruments typically utilize lasers with repetition rates below 100 Hz since in most cases this regime provides a good balance of sampling frequency and laser pulse energy. However, measuring large sample areas of a several cm2 with high spatial resolution (<10 μm), at this frequency rate would be very time consuming since millions of spectral data points need to be collected in order to create a high-resolution image (3 h–15 h per cm2). In this work, we explore the approach to reduce, the acquisition time for high resolution LIBS imaging, or so-called μ-LIBS imaging, by using a laser operating in the kHz pulse repetition frequency (PRF) range. As a result, we describe and demonstrate a μ-LIBS imaging microscope which can image >6 cm2 sample areas with about 10 μm resolution in significantly shorter time (<20 min/cm2). The developed system opens a potential for variety of application fields where knowledge of elemental composition and elemental distribution is needed to perform conclusive analysis.