Laser-induced bubbles (jetting)

Cavitation jetting has to be one of the coolest things a bubble can do!

When ‘something’ causes a bubble to collapse asymmetrically (i.e. one side more than the other), then a jet can form. A lot of the potential energy stored in the bubble, at its maximum radius, is converted to the kinetic energy of a spike of liquid that pierces through the bubble. If this jet hits a piece of metal, it leaves a little dent, they pack such a punch.

jetL2gifjetMgifjetR2gif

 

 

 

 

 

CavLab demonstrated that you could use a burst of focused ultrasound to direct (control?) these jets. If you put the ultrasound focus just to the left of the bubble then the jet shoots off to the right (3rd movie above). This happen because the ultrasound exerts a radiation force on the bubble during its deflation, as the ‘something’ that causes the asymmetric collapse.