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Title: Ultrashort pulse high repetition rate laser system for biological tissue processing

A method and apparatus is disclosed for fast, efficient, precise and damage-free biological tissue removal using an ultrashort pulse duration laser system operating at high pulse repetition rates. The duration of each laser pulse is on the order of about 1 fs to less than 50 ps such that energy deposition is localized in a small depth and occurs before significant hydrodynamic motion and thermal conduction, leading to collateral damage, can take place. The depth of material removed per pulse is on the order of about 1 micrometer, and the minimal thermal and mechanical effects associated with this ablation method allows for high repetition rate operation, in the region 10 to over 1000 Hertz, which, in turn, achieves high material removal rates. The input laser energy per ablated volume of tissue is small, and the energy density required to ablate material decreases with decreasing pulse width. The ablation threshold and ablation rate are only weakly dependent on tissue type and condition, allowing for maximum flexibility of use in various biological tissue removal applications. The use of a chirped-pulse amplified Titanium-doped sapphire laser is disclosed as the source in one embodiment.
Inventors:
 [1];  [2];  [3];  [4];  [5];  [4];  [4];  [4]
  1. (Laguna Beach, CA)
  2. (Danville, CA)
  3. (Moss Beach, CA)
  4. (Livermore, CA)
  5. (Fremont, CA)
Issue Date:
OSTI Identifier:
871382
Assignee:
Regents of University of California (Oakland, CA) OAK
Patent Number(s):
US 5720894
Contract Number:
FG03-91ER61227
Research Org:
University of California
Country of Publication:
United States
Language:
English
Subject:
ultrashort; pulse; repetition; rate; laser; biological; tissue; processing; method; apparatus; disclosed; fast; efficient; precise; damage-free; removal; duration; operating; rates; fs; 50; energy; deposition; localized; depth; occurs; significant; hydrodynamic; motion; thermal; conduction; leading; collateral; damage; material; removed; micrometer; minimal; mechanical; effects; associated; ablation; allows; operation; region; 10; 1000; hertz; achieves; input; ablated; volume; density; required; ablate; decreases; decreasing; width; threshold; weakly; dependent; type; condition; allowing; maximum; flexibility; various; applications; chirped-pulse; amplified; titanium-doped; sapphire; source; embodiment; repetition rates; energy density; pulse repetition; repetition rate; pulse width; laser pulse; laser energy; pulse duration; energy deposition; biological tissue; method allows; rate laser; rate operation; thermal conduction; various biological; minimal thermal; input laser; material removed; sapphire laser; removal rates; removal rate; ultrashort pulse; method allow; ablate material; material removal; /216/156/606/607/