Comparison of Time Reversal and Time Reversal Plus Ultrasonic Tagging (VIDEO)
Caption
In both cases photons take random paths through tissue. Some are lost (blue) but others (green) will reach the mirror on the other side of the tissue. The mirror is a special phase conjugate mirror that turns the light around and sends it back on its original path, as though time had been reversed. Clever as this is, by itself it isn't very useful because the light scatters again as is backtracks (left). In the new method, called TRUE, ultrasound is focused into the tissue (small black ring). Light passing through the ultrasound field is tagged by it and selectively returned by the mirror to its virtual source, the ultrasound focus (right). Instead of scattering, the light is brought to a focus inside the tissue.
Credit
Lihong Wang
Usage Restrictions
None
License
Licensed content