High-power laser has been considered as a potential method of rock breakage through melting. However, high energy consumption and low efficiency are the main restrictions for applying laser technology in rock excavation and fragmentation. A new rock breakage method which combines pulsed laser and induced cavitation is described in this paper, with potentially low energy consumption and high efficiency in rock fracturing. Cavitation is the rapid formation and collapse of vapour bubbles within a liquid. The irradiation of a pulsed laser beam with the energy density beyond the breakdown threshold of a liquid could induce cavitation bubbles in the liquid. The energy of the laser beam converts into highly pressurised cavitation bubbles. When the cavitation bubbles explode near rock surface, the explosions induce dynamic force to break the rock. In this paper, a series of tests using continuous and pulsed laser beams to break rocks in both air and water are presented. It is found that the pulsed laser in water produced the best rock-breaking efficiency without melting the rocks. Further analysis of the crater morphology and mechanical properties suggests the dynamic force at cavitation bubble explosion is the main cause of rock fracturing. The study leads to the conclusion that the pulsed laser induced cavitation in water is potentially an effective way for laser rock cutting technology with industrial applications.

中文翻译：

---

脉冲激光诱导的空化气泡增强了岩石破裂：初步的实验观察和结论

高功率激光已被认为是通过熔化破坏岩石的一种潜在方法。然而，高能量消耗和低效率是将激光技术应用于岩石开挖和破碎的主要限制。本文介绍了一种结合脉冲激光和诱导空化的新型岩石破碎方法，具有潜在的低能耗和高效率的岩石破碎效果。空化是液体中蒸气气泡的快速形成和破裂。能量密度超过液体击穿阈值的脉冲激光束辐照会在液体中引起空化气泡。激光束的能量转换为高压气穴气泡。当空化气泡在岩石表面附近爆炸时，爆炸会引起动力使岩石破裂。在本文中，提出了一系列使用连续和脉冲激光束破坏空气和水中岩石的测试。发现水中的脉冲激光在不使岩石融化的情况下产生了最佳的碎石效率。对火山口形态和力学性能的进一步分析表明，空化气泡爆炸时的动力是岩石破裂的主要原因。该研究得出的结论是，脉冲激光诱导的水蚀是工业上激光切割技术的有效途径。对火山口形态和力学性能的进一步分析表明，空化气泡爆炸时的动力是岩石破裂的主要原因。该研究得出的结论是，脉冲激光诱导的水蚀是工业上激光切割技术的有效途径。对火山口形态和力学性能的进一步分析表明，空化气泡爆炸时的动力是岩石破裂的主要原因。该研究得出的结论是，脉冲激光诱导的水蚀是工业上激光切割技术的有效途径。