LIBS spectroscopy setup

Expansion of the existing ablation equipment in order to accurately focus the beam of the Nd:YAG ablation laser at fundamental and second harmonic frequencies, accurately control the area ablated by this laser, accurately control the area of optical signal collection from the ablation plume and accurately move larger samples.

The system supplied as a single unique unit had to be compatible with the technical parameters of the existing equipment, i.e. the dimensions of the ablation chamber, the spectral range of the ablation laser and the optical system of the spectrometer.

The existing ablation system consisted of a high-resolution echelle spectrograph (ESA WIN 4000, LLA Instruments GmBH, Germany) and a custom-built vacuum chamber (Vakuum Praha s.r.o., Czech Republic).

In September 2019, we designed, manufactured and delivered a LIBS spectroscopy setup for the J. Heyrovsky Institute of Physical Chemistry of the CAS. This was an extension of the existing setup (Nd:YAG laser, vacuum chamber, spectrograph) for laser-excited plasma spectroscopy with an optical path inside the vacuum chamber, with focusing optics for the laser, sample shift in XYZ axes and a view camera allowing precise focusing of the laser beam on the sample surface.

The programmable movement of the samples by means of the displacements also enables surface analysis and the generation of 2D maps (or, in combination with depth profiling, 3D maps) of the elemental distribution in the sample.

The assembly is equipped with an optical system for collecting the microplasma radiation and analyzing it with a spectrograph outside the sample chamber, as well as control electronics and software that allow programming of the automatic sample displacement.

Parameters of the device

• Automatic sample positioning with a range of 75 mm in all axes (resolution below 1 um), load capacity 2 kg
• Covered optical path, laser beam guidance to sample
• Motorised focal position control with 3 cm range (8 nm resolution)
• Motorised position control of optics for optical signal acquisition
• Assembly mounted on a breadboard with a network of M6 threads, easy to remove the entire experiment from the vacuum chamber and use the chamber for another experiment
• Preview camera for precise localization of the analyzed spot on the sample