The remote LIBS system uses a Nd:Yag pulsed laser at 1064nm with pulse duration ~5ns that focuses 40mJ of light into a spot size of ~1 mm to ablate the material. The pulse energy can be adjusted and can ablate successive layers in depth by applying multiple laser pulses. A telescope collects light from the plume and directs it through a fibre to a set of spectrometers covering the range from ~200nm to ~900nm with spectral resolution of ~0.2nm. Both the laser and the collection optics are placed on computer controlled pan/tilt stages. A small camera is attached to record the area of analysis.
Potential Results
The main advantage of remote LIBS is that the elemental analysis (all elements including the light elements) can be performed at distances up to tens of metres from one position on the ground level which is convenient and allows the analysis at inaccessible positions on a monument/object. The elemental analysis provides complementary information to remote Raman/LIF and remote reflectance spectral imaging. By controlling the pulse energy, the elemental composition can be identified layer by layer by applying multiple pulses.