In this work, the main peculiarities of Laser Induced Plasma (LIP) in liquid have been investigated by comparing the evolution of the LIP in water and in air. To this end, fast shadowgraphy and temporally resolved emission spectroscopy were used. The experimental results reveal a scenario where plasma under water remains in a high-density state, characterized by the condensation of electronic levels as a consequence of the confinement effect of the surrounding water. In this case, the plasma emission spectrum consists of continuum radiation. In contrast, LIP in air expands, reaching an ideal plasma state in a few hundred nanoseconds. In this condition, excited electronic levels are enabled and the spectrum is characterized by discrete emission lines, according to the Boltzmann statistics. These differences allow LIP in liquid and gas to be used in a wide variety of applications, ranging from analytical chemistry to nanomaterial production.

中文翻译：

---

气体和液体中激光诱导等离子体的比较

在这项工作中，通过比较 LIP 在水中和空气中的演变，研究了液体中激光诱导等离子体 (LIP) 的主要特性。为此，使用了快速阴影成像和时间分辨发射光谱。实验结果揭示了水下等离子体保持高密度状态的场景，其特征是由于周围水的限制效应导致电子能级的凝聚。在这种情况下，等离子体发射光谱由连续辐射组成。相比之下，空气中的 LIP 会膨胀，在几百纳秒内达到理想的等离子体状态。根据玻尔兹曼统计，在这种情况下，激发的电子能级被启用，并且光谱以离散的发射线为特征。