Ultrasound laser-induced breakdown spectroscopy and acoustic spectroscopy of resonance inclusions in liquids

We have used a nanosecond pulsed laser to study the dynamics of laser- induced breakdown with traditional optical detection on both nanosecond time scale and at later stages. Experiments on the induction of optical breakdown in the volume of liquid were performed using an Nd:YAG laser. It is shown that the optical breakdown in the liquid in the ultrasonic field is accompanied by an increase in the intensity of the spectral lines of potassium and oxygen with an increase in the amplitude and frequency of ultrasound. It was found that the effect of ultrasound on the intensity of the lines varies depending on the time of the breakdown evolution. Along with the optical spectra, the acoustic emission accompanying the pulsations of the cavitation bubble formed at the late stages of liquid breakdown source was studied. It was shown that the acoustic emission varies significantly with different ultrasound parameters. It is shown that an excited signal at its own switching frequency has a sufficiently high amplitude for its registration under typical experimental conditions. It is shown that the saturation effect is observed at frequencies above 200 kHz and at high ultrasound power, when the growth of the intensity of spectral lines slows down sharply. This effect indicates the possibility of using relatively small ultrasound powers for the implementation of the identified optoacoustic effects and spectroscopic properties in the laser breakdown in the liquid.