Electronic temperature characteristics of laser-induced Fe plasma in fruits

Abstract

<jats:title>Abstract</jats:title><jats:p>Fruit is not only delicious, but it also contains iron, potassium, magnesium, and other microelements necessary for the human body. Banana, pineapple and kiwifruit were selected as samples for testing. A laser with a wavelength of 532 nm was focused on the samples’ surface to generate a plasma. The emission spectrum of the atoms and ions in the plasma were collected by optical receivers, and the optimal condition was confirmed by analyzing the signal-to-noise ratio. The electronic temperature characteristics of the Fe plasma were studied under optimal experimental conditions. The maximum electron temperature of the Fe plasma occurred after a time delay of 300 ns in bananas, after 400 ns in pineapples and after 400 ns in kiwifruit. The electronic temperature of the Fe plasma increased with the time delay before the maximum point was reached. However, the temperature decreased after the maximum point was reached. At the beginning of the decline, the plasma decreased rapidly, but later decreased slowly. The range of the variation of the electron temperature of the Fe plasma in bananas, pineapples, and kiwifruits was 12388.29–19958.3 K, 11994.21–16856.4 K, and 13388.2–19607.32 K, respectively.</jats:p>

Spatiotemporal spectroscopic characterization of plasmas induced by non-orthogonal laser ablation

“…Similar temperatures (in the order of 1E+4 K) have been commonly reported for orthogonal ablation with pulse energies ranging from 20 mJ to 200 mJ [34][35][36][37][38] , which validates our results. Overall, the observed temporal evolution of the temperature is in good agreement with existing reports [39][40][41][42][43] . In addition, for each plasma, the ionization fraction calculated according to (1,2) approached unity, which is in line with studies of orthogonal ablation 44 .…”