Low-threshold cavitation in water using IR laser pulse trains

Area of Science:

• Physics
• Acoustics
• Biomedical Engineering

Background:

• Cavitational disruption is a key phenomenon in various physical and biological processes.
• Laser-induced cavitation offers potential for controlled material modification and surgical applications.
• Understanding the energy thresholds and physical parameters of laser cavitation is crucial for developing new technologies.

Purpose of the Study:

• To demonstrate low-temperature cavitational disruption in water using trains of laser pulses.
• To determine the fragmentation threshold energy density per pulse.
• To investigate the associated negative pressure amplitude and temperature changes.

Main Methods:

• Utilizing a Raman laser to generate trains of laser pulses at a wavelength of 1626 nm.
• Inducing cavitational disruption in water.
• Measuring the energy density per pulse and the amplitude of negative pressure.
• Monitoring the temperature jump during the process.

Main Results:

• Successful demonstration of low-temperature cavitational disruption in water.
• Estimated mean fragmentation threshold energy density per pulse of 7.2x10^6 J/m^3.
• Observed negative pressure amplitude of 6-7 bars.
• Minimal temperature jump of approximately 2 degrees C.

Conclusions:

• Low-temperature cavitational disruption in water can be achieved with trains of laser pulses.
• The identified energy threshold and pressure parameters are significant for understanding the phenomenon.
• This research supports the development of precision nonthermal cavitational laser surgery techniques.