Analysis of laser induced plasmas for disparate samples by shadowgraphy

abstract

en

Laser Induced Breakdown Spectroscopy (LIBS) is a method typical for fast and dynamic process of sample ablation (Miziolek -LIBS). It is also known for pulse-to-pulse signal fluctuation. This is caused by several circumstances, such as experimental parameters, instability of the laser or the plasma itself (Buday et.al 2020), heterogeneity of the sample etc. To improve stability of the method, scientists have been mainly focused on optimizing the experimental system, implementing new techniques or creating new data processing systems. One of the possibilities how to improve performance of LIBS is to deeply understand dynamics of the laser-matter interaction and consecutive plasma dynamics. Our work is focused on using shadowgraphy system for observation of the pressure wave created by the plasma expansion, that would lead to better understanding of plasma dynamics under different experimental parameters. We studied several samples with completely different matrices, such as glass, bronze and soft tissues. These samples were studied under different laser fluences in air atmosphere and the shadowgraphy data were taken in the range 100 ns to 10 µs, providing data in large time window compared to plasmas lifetime. Information about size and speed of the pressure wave were measured and lastly compared between different samples.

Laser Induced Breakdown Spectroscopy (LIBS) is a method typical for fast and dynamic process of sample ablation (Miziolek -LIBS). It is also known for pulse-to-pulse signal fluctuation. This is caused by several circumstances, such as experimental parameters, instability of the laser or the plasma itself (Buday et.al 2020), heterogeneity of the sample etc. To improve stability of the method, scientists have been mainly focused on optimizing the experimental system, implementing new techniques or creating new data processing systems. One of the possibilities how to improve performance of LIBS is to deeply understand dynamics of the laser-matter interaction and consecutive plasma dynamics. Our work is focused on using shadowgraphy system for observation of the pressure wave created by the plasma expansion, that would lead to better understanding of plasma dynamics under different experimental parameters. We studied several samples with completely different matrices, such as glass, bronze and soft tissues. These samples were studied under different laser fluences in air atmosphere and the shadowgraphy data were taken in the range 100 ns to 10 µs, providing data in large time window compared to plasmas lifetime. Information about size and speed of the pressure wave were measured and lastly compared between different samples.

LIBS, plasma, shadowgraphy

21.09.2020

Kyoto

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