Patent ID: 7002169

Claim:
A method of generating photons by sonoluminescence, said method comprising at least the following steps: (a) generating at least one standing acoustic wave (S 1 ) in a liquid reservoir ( 2 ), said standing acoustic wave having at least one antinode; (b) trapping at least one gas bubble ( 5 ) in the liquid at said antinode of the standing acoustic wave, said gas bubble then being subjected to a periodic deformation cycle comprising expansion stages ( 10 ) and contraction stages ( 12 ) in alternation; and (e) generating acoustic wave impulses (S 2 ) in the liquid, which compression acoustic wave impulse are superposed on the standing acoustic wave (S 1 ), and cause photons to be emitted by the gas bubble, by sonoluminescence; said method being characterized in that the acoustic wave impulses (S 2 ) are caused to be emitted by a number n at least equal to 2 of impulse firing transducers (T 1 –T 8 ) disposed around the gas bubble ( 5 ); in that a focusing training step (c) and a synchronization step (d) 0 are interposed between the steps (b) and (e); and in that, during the focusing training step (c), the impulse firing transducers are caused to emit acoustic wave impulses (S 2 ) with a first amplitude that is sufficiently small to avoid disturbing significantly the position and the deformation cycle of the gas bubble ( 5 ), acoustic signals generated by said acoustic wave impulse in the liquid reservoir are measured, and time offsets are deduced therefrom to be applied to respective (T 1 –T 8 ) so as to focus said acoustic wave impulses onto the gas bubble ( 5 ); in that, during the step (d), instants at which acoustic wave impulses (S 2 ) are emitted by the various impulse firing transducers (T 1 –T 8 ) are determined so that each wave impulse ( 2 ) generated by the impulse firing transducers reaches the gas bubble ( 5 ) either during a contraction stage if the wave impulse is compression wave, or during an expansion stage if the wave impulse is an expansion wave; and in that, during the step (e), the impulse firing transducers (T 1 –T 8 ) are caused to generate the acoustic wave impulses at the respective emit instants determined at the step (d), with a second amplitude that is large than the first amplitude.