Abstract Studies of the opto-acoustic effects accompanying laser breakdown in water generated by focused laser and ultrasonic radiation are performed. For the first time, the experimental results were obtained showing sharply increasing effects of acoustic emission from the breakdown zone under the combined influence of laser and ultrasonic irradiation. Experiments were performed using the nanosecond pulses of a Nd:YAG laser operating at a wavelength of 532 nm. Acoustic radiation was generated by acoustic focusing systems at various frequencies. It is shown that recording of acoustic emission from the breakdown zone makes it possible to study the thresholds and dynamics of the laser breakdown, which coincide with the high-speed optical methods. The results obtained make it possible to find applications of the acoustic method of diagnostics of laser breakdown and cavitation in opaque environments for which optical methods are not applicable. The effect of the increase in the resolution of the spectral lines of chemical elements in seawater under the action of an ultrasonic field is established. This effect indicates the possibility of development of a combined method of laser–spark spectroscopy using ultrasound, which will make it possible to approach the sensitivity of the precision chemical analysis, and which should be more practical and advanced because it yields a high efficiency and detailed measurements.

中文翻译：

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超声波场中海水的激光击穿的光声效应

摘要 研究了聚焦激光和超声辐射在水中伴随激光击穿的光声效应。首次获得的实验结果表明，在激光和超声辐照的共同影响下，击穿区的声发射效应急剧增加。使用工作在 532 nm 波长的 Nd:YAG 激光器的纳秒脉冲进行实验。声辐射是由声学聚焦系统在不同频率下产生的。结果表明，记录击穿区的声发射可以研究激光击穿的阈值和动力学，这与高速光学方法相吻合。获得的结果使得在光学方法不适用的不透明环境中找到激光击穿和空化诊断的声学方法的应用成为可能。建立了在超声波场作用下海水中化学元素谱线分辨率增加的效果。这种效应表明开发一种使用超声波的激光-火花光谱组合方法的可能性，这将使接近精密化学分析的灵敏度成为可能，并且应该更加实用和先进，因为它产生了高效率和详细测量。建立了在超声波场作用下海水中化学元素谱线分辨率增加的效果。这种效应表明开发一种使用超声波的激光-火花光谱组合方法的可能性，这将使接近精密化学分析的灵敏度成为可能，并且应该更加实用和先进，因为它产生了高效率和详细测量。建立了在超声波场作用下海水中化学元素谱线分辨率增加的效果。这种效应表明开发一种使用超声波的激光-火花光谱组合方法的可能性，这将使接近精密化学分析的灵敏度成为可能，并且应该更加实用和先进，因为它产生了高效率和详细测量。