Publication details
Hyphenated acoustic/optical emission spectroscopic data from laser-induced sparks to geological material characterisation
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| Year of publication | 2023 |
| Type | Appeared in Conference without Proceedings |
| MU Faculty or unit | |
| Citation | |
| Description | The acoustic emission accompanying laser-induced plasmas have been used for decades for multiple purposes as a monitoring signal of the ablation process, as a correction/normalisation factor of shot-to-shot plasma inherent instabilities, to characterise the focal position, to elucidate essential parameters during the inspection of surfaces and as an observable capable of detecting and recognising a material [1]. In this context, the recent integration of a microphone synchronised to the LIBS laser in the Perseverance rover deployed as part of the NASA mission Mars 2020 has re-kindle the motivation towards comprehending the acoustic sound waves from the laser-generated sparks, mainly to be exploited as a new characterising tool complementary to the optical emission response of plasmas. In this research, the multiple factors that may be conditioning acoustic from laser-induced plasmas have been evaluated, from the sample-related traits (physical properties like dimensions, colour, porosity, ...), to the boundary conditions governing the workspace where the inspected sample may be placed (the nature of the terrain over which the sound propagates, the presence of the obstacles ...) without neglecting the coordinates that locate the sender (the plasma) and the receiver (the mic). Furthermore, the influence of the instrumentation (laser wavelength, type of microphone, ...) on the ensuing acoustic waveform has also been investigated. With all this, possibilities of combining simultaneous acoustic and optical data from plasmas from laser ablation scanning of the surface of a geological material through a dual mapping have been evaluated to develop a methodology that allows multidimensional micro-scale characterisation of mineral phases. For the first time, hyphenated acoustic/optical emission spectroscopic data resulting from micro plasmas induced by short laser pulses may suppose a synergy on exploration at the microscopic level of solid bodies in the Solar System to help a better interpretation past geological conditions and the possible processes that have occurred, and for ascertaining the putative presence of evidence of life, if any. |