LIBS is a type of optical emission spectroscopy used to measure elemental concentrations in a material.
LIBS operates by using a pulsed, focused laser that is fired at a sample with sufficient pulse energy as to create a plasma around the area struck. Bound atomic electrons are striped from the atoms comprising the material. As the plasma cools, atoms recombine with electrons and in the process emit light in the UV, optical and IR regimes.
LIBS has been used for more than 30 years as a laboratory technique, capable of analyzing any element in the periodic table. Recently, the technique has been miniaturized into a handheld device (HH LIBS) capable of analyzer any element, depending on the spectrometer range chosen for the device.
A pulsed laser, typically in the 5-6 mJ/pulse energy range and pulsing 50 times per second (50 Hz) is fired at a sample. The laser passes through a focusing lens, to focus the laser beam down to approximately a 50 um diameter. The pulse duration is 1-2 ns (billionths of a second) thus yielding a high enough power density (energy/area/time) to vaporize the material producing a plasma.
As the plasma cools over a few hundred micro-seconds, the electrons that were stripped from the atoms recombine with the atoms, emitting light in the UV, optical and infra-red spectrum.
An on-board spectrometer analyzes the emitted light by measuring the wavelength and intensity (amount) of light at specific wavelengths – the optical spectrum.
On-board software compares the spectral lines with known wavelengths to identify what elements are present, and uses the intensity of those lines with an on-board calibration, to quantify the concentration of the element.