# US 2018/0021086 A1 · Laser-directed microcavitation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0021086 A1 - Document ID: US20180021086A1 - Status: Published application - Kind: A1 - Application number: 15/670,277 - Filed: 2017-08-07 - Published: 2018-01-25 - Earliest claimed: 2014-05-28 - Assignees: Institut National D'Optique - Applicants: Institut National D'Optique - Inventors: Pascal DELADURANTAYE; Ozzy MERMUT - Web page: https://patentgrep.com/patent/US20180021086A1 ## CPC - A61B 18/20: using laser - A61B 18/22: the beam being directed along or through a flexible conduit, e.g. an optical fibre; {Couplings or} hand-pieces therefor - A61F 9/008: using laser - A61F 9/00814: {Laser features or special beam parameters therefor} - C12N 13/00: Treatment of microorganisms or enzymes with electrical or wave energy, e.g. magnetism, sonic waves - G01N 33/5005: {involving human or animal cells (immunoassay G01N33/56966; immunoassays of protozoa G01N33/56905; protozoa in screening assays C12Q1/025)} - A61B 2017/00159: {Pulse shapes} - A61B 2017/00185: {Means for setting or varying the pulse height} - A61B 2018/00511: {Kidney} - A61B 2018/00535: {Biliary tract} - A61B 2018/00577: {Ablation} - A61B 2018/2035: {Beam shaping or redirecting; Optical components therefor (A61B2018/2255 takes precedence)} - A61B 2018/20355: {Special scanning path or conditions, e.g. spiral, raster or providing spot overlap} - A61B 2018/206: {the laser light passing along a liquid-filled conduit} - A61B 2018/2255: {Optical elements at the distal end of probe tips} - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - A61F: FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS (dental prosthetics A61C) - C12N: MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA (microbiological testing media C12Q1/00) - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) ## Abstract Methods and systems for the controlled generation of bubbles in a medium having a liquid phase are generally provided. Laser pulses having a time-dependent pulse parameter controllable over their duration are generated. The medium is irradiated with the laser pulses with a radiant exposure sufficient to initiate microcavitation within the medium during each laser pulse. The time-dependent pulse parameter of each laser pulse is controlled according to a generally positive variation over the pulse duration such that the medium absorbs a greater quantity of energy from the laser pulse at an end of the pulse duration than at a beginning thereof. Such methods and systems may be used for various applications such as biology, medicine or material processing. ## Claims ### Claim 1 A method for the generation, in a medium having a liquid phase, of microcavitation bubbles of maximum volume controlled over at least twice a threshold radiant exposure, comprising: using a laser system comprising a pulse shaping mechanism, generating one or more laser pulses, each laser pulse having a pulse duration between 1 ns and 5000 ns and an energy selected to deliver a radiant exposure sufficient to initiate microcavitation within the medium during said pulse duration, each laser pulse having a tailored amplitude profile selected to deliver a greater quantity of energy to the medium during an end portion of the pulse duration than during a beginning portion thereof; and irradiating the medium with the laser pulses. ### Claim 2 (depends on 1) The method according to claim 1, wherein the pulse shaping mechanism comprises a digital pulse shaping module. ### Claim 3 (depends on 2) The method according to claim 2, wherein the laser system comprises a seed light source and first and second amplitude modulators, the digital pulse shaping module providing control signals to the first and second amplitude modulators. ### Claim 4 (depends on 1) The method according to claim 1, wherein the pulse shaping mechanism comprises a pulse generator electrically driving a seed light source. ### Claim 5 (depends on 1) The method according to claim 1, wherein the tailored amplitude profile of each light pulse defines a sawtooth-like shape having a positive slope. ### Claim 6 (depends on 1) The method according to claim 1, wherein the tailored amplitude profile of each light pulse defines a first phase of regularly increasing amplitude followed by a second phase of decreasing amplitude, the second phase being shorter than the first phase. ### Claim 7 (depends on 1) The method according to claim 1, wherein the tailored amplitude profile of each light pulse defines an initial step followed by an increasing amplitude phase and a decreasing amplitude phase, sequentially. ### Claim 8 (depends on 1) The method according to claim 1, wherein the tailored amplitude profile of each light pulse defines a sequence of sub-pulses of gradually increasing peak amplitude. ### Claim 9 (depends on 1) The method according to claim 1, wherein the tailored amplitude profile of each light pulse has a negative skew. ### Claim 10 A method for the generation, in a medium having a liquid phase, of microcavitation bubbles of maximum volume controlled over at least twice a threshold radiant exposure, comprising: using a laser system comprising a spectral tailoring module, generating one or more laser pulses, each laser pulse having a pulse duration and an energy selected to deliver a radiant exposure sufficient to initiate microcavitation within the medium during said pulse duration, each laser pulse having a tailored spectral profile selected to deliver a greater quantity of energy to the medium during an end portion of the pulse duration than during a beginning portion thereof; and irradiating the medium with the laser pulses. ### Claim 11 (depends on 10) The method according to claim 10, wherein the spectral tailoring module comprises a seed light source generating seed laser pulses, and a phase modulator imposing a time-dependent phase variation on each of said seed laser pulses. ### Claim 12 (depends on 10) The method according to claim 10, wherein the pulse duration is between 1 ns and 5000 ns. ### Claim 13 (depends on 10) The method according to claim 10, wherein said tailored spectral profile comprises wavelengths at the end of the pulse duration which are more strongly absorbed by the medium than wavelengths at the beginning of the pulse duration. ### Claim 14 (depends on 10) The method according to claim 10, wherein the tailored amplitude profile of each light pulse has a negative skew. ### Claim 15 A method for the generation, in a medium having a liquid phase, of microcavitation bubbles of maximum volume controlled over at least twice a threshold radiant exposure, comprising: using a laser system comprising a spatial tailoring module, generating one or more laser pulses, each laser pulse having a pulse duration and an energy selected to deliver a radiant exposure sufficient to initiate microcavitation within the medium during said pulse duration, each laser pulse having a tailored spatial profile selected to deliver a greater quantity of energy to the medium during an end portion of the pulse duration than during a beginning portion thereof; and irradiating the medium with the laser pulses. ### Claim 16 (depends on 15) The method according to claim 15, wherein the pulse duration is between 1 ns and 5000 ns.