Sonoluminescence is the production of light from sound. This effect, discovered just
over ten years ago, has been, and continues to be, the subject of
considerable experimental and theoretical research.
Sonoluminescence (SL) refers to the phenomena in which a
micron size gas bubble is both spatially trapped and
oscillated by an acoustic field in such a way that on each
compression of the bubble a small burst of light is
emitted. This light emission is in the form of extremely
short bursts (< 100ps), but is periodic, occuring in
phase with each and every cycle of the driving pressure
field. Each bubble collapse produces about 500,000 photons.
The bubble collapse is so violent that some predicted
theoretical accelerations are larger than those associated
with a Black Hole! The actual emission mechanism has not yet
been explained, although theories are as plentiful as they are diverse.
Students begin their exploration by first understanding some
basic acoustical principles, such as resonance behavior,
quality factors, variation of sound speed with temperature,
and the eigenmode structure of a 3-dimensional resonance "cavity." Once these principles are understood there are a
large number of experiments that can be performed focusing on
the liquid sample preparation and the light emitted from the bubble.