Extending the potential of plasma-induced luminescence spectroscopy

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In the context of laser-induced breakdown spectroscopy (LIBS), plasma-induced luminescence (PIL) may be observed by tuning the temporal acquisition parameters (delay and gate). This approach provides useful information about minor elements in a sample. The broad range of excitation resulting from the laser-induced plasma enables the simultaneous observation of multiple luminescence emission bands. However, PIL results in damage to the sample due to laser ablation. Moreover, time resolution only enables the separation of emission signatures with different decay times; as a consequence, only luminescence signatures with long decay times may be observed separately from plasma emissions. In this study, we propose a new experimental approach to extend the potential of PIL spectroscopy. Our main idea is to generate a laser-induced plasma on a separate ablation target adjacent to the luminescent sample, which is hence protected from laser ablation. Moreover, the ablation target can be selected to ensure a stable plasma for PIL excitation. We also show that this setup enables the further study of the excitation mechanisms of PIL itself by varying the nature of the excitation source of PIL. Finally, we propose a new experimental setup that enables the study of the luminescence features of short decay times. We successfully tested this new approach on both artificial and natural crystals, showing luminescence emission bands of varying decay times.