US5656186A
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Method for controlling configuration of laser induced breakdown and ablation
Assignee: University of Michigan (System)
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Filing: 1994-04-08
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Granted: 1997-08-12
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Expires: 2014-04-08
Abstract
Abstract In one aspect the invention provides a method for laser induced breakdown of a material with a pulsed laser beam where the material is characterized by a relationship of fluence breakdown threshold (Fth) versus laser beam pulse width (T) that exhibits an abrupt, rapid, and distinct change or at least a clearly detectable and distinct change in slope at a predetermined laser pulse width value. The method comprises generating a beam of laser pulses in which each pulse has a pulse width equal to or less than the predetermined laser pulse width value. The beam is focused to a point at or beneath the surface of a material where laser induced breakdown is desired. The beam may be used in combination with a mask in the beam path. The beam or mask may be moved in the x, y, and Z directions to produce desired features. The technique can produce features smaller than the spot size and Rayleigh range due to enhanced damage threshold accuracy in the short pulse regime.
Inventors
- 👤 Gerard A. Mourou
- 👤 Detao Du
- 👤 Subrata K. Dutta
- 👤 Victor Elner
- 👤 Ron Kurtz
- 👤 Paul R. Lichter
- 👤 Xinbing Liu
- 👤 Peter P. Pronko
- 👤 Jeffrey A. Squier
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 15:34
CPC Classifications
B; B23; B23K; B23K26/00; B23K26/02; B23K26/06; B23K26/062; B23K26/0622; B23K26/0624; A; A61; A61B; A61B18/00; A61B18/18; A61B18/20; A61F; A61F9/00; A61F9/007; A61F9/008; A61F9/00825; B23K26/064; B23K26/066; B23K26/36; B23K26/38; B23K26/382; B23K26/40; B23K26/50; B23K26/53; B23K2101/00; B23K2101/36; B23K2101/40; B23K2103/00; B23K2103/08; B23K2103/10; B23K2103/50; B23K2103/54
Claims Analysis
Total Claims: 52
Claim 1
Independent Claim
95 words
A method for laser induced breakdown (LIB) of a material with a pulsed laser beam, the material being characterized by a relationship of fluence breakdown threshold versus laser pulse width that exhibits a rapid and distinct change in slope at a characteristic laser pulse width, said method comprising the steps of: a. generating a beam of one or more laser pulses in which each pulse has a pulse width equal to or less than said characteristic laser pulse width; and b. focusing said beam to a point at or beneath the surface of the material.
Claim 2
Independent Claim
95 words
A method for laser induced breakdown (LIB) of a material with a pulsed laser beam, the material being characterized by a relationship of fluence breakdown threshold versus laser pulse width that exhibits a rapid and distinct change in slope at a characteristic laser pulse width, said method comprising the steps of: a. generating a beam of one or more laser pulses in which each pulse has a pulse width equal to or less than said characteristic laser pulse width; and b. focusing said beam to a point at or beneath the surface of the material.
Claim 3
Dependent Claim
32 words
The method according to claim 1 wherein the material is a metal, the pulse width is 10 to 10,000 femtoseconds, and the beam has an energy of 1 nanojoule to 1 microjoule.
Claim 4
Dependent Claim
29 words
The method according to claim 1 wherein the spot size is varied within a range of 1 to 100 microns by changing the f number of the laser beam.
Claim 5
Dependent Claim
25 words
The method according to claim 1 wherein the spot size is varied within a range of 1 to 100 microns by varying the target position.
Claim 6
Dependent Claim
37 words
The method according to claim 1 wherein the material is transparent to radiation emitted by the laser and the pulse width is 10 to 10,000 femtoseconds, the beam has an energy of 10 nanojoules to 1 millijoule.
Claim 7
Dependent Claim
32 words
The method according to claim 1 wherein the material is biological tissue, the pulse width is 10 to 10,000 femtoseconds and the beam has an energy of 10 nanojoules to 1 millijoule.
Claim 8
Independent Claim
139 words
A method for laser induced breakdown (LIB) of a material with a pulsed laser beam, the material being characterized by a relationship of fluence breakdown threshold versus laser pulse width that exhibits a rapid and distinct change in slope at a predetermined laser pulse width where the onset of plasma induced breakdown occurs, said method comprising the steps of: a. generating a beam of one or more laser pulses in which each pulse has a pulse width equal to or less than said predetermined laser pulse width obtained by determining the ablation (LIB) threshold of the material as a function of pulse width and by determining where the ablation (LIB) threshold function is no longer proportional to the square root of pulse width; and b. focusing said beam to a point at or beneath the surface of the material.
Claim 9
Independent Claim
139 words
A method for laser induced breakdown (LIB) of a material with a pulsed laser beam, the material being characterized by a relationship of fluence breakdown threshold versus laser pulse width that exhibits a rapid and distinct change in slope at a predetermined laser pulse width where the onset of plasma induced breakdown occurs, said method comprising the steps of: a. generating a beam of one or more laser pulses in which each pulse has a pulse width equal to or less than said predetermined laser pulse width obtained by determining the ablation (LIB) threshold of the material as a function of pulse width and by determining where the ablation (LIB) threshold function is no longer proportional to the square root of pulse width; and b. focusing said beam to a point at or beneath the surface of the material.
Claim 10
Dependent Claim
22 words
The method according to claim 1 wherein the laser beam has an energy in a range of 10 nanojoules to 1 millijoule.
Claim 11
Dependent Claim
28 words
The method according to claim 1 wherein the laser beam has a fluence in a range of 100 millijoules per square centimeter to 100 joules per square centimeter.
Claim 12
Dependent Claim
36 words
The method according to claim 1 wherein the laser beam defines a spot in or on the material and the LIB causes ablation of an area having a size smaller than the area of the spot.
Claim 13
Dependent Claim
22 words
The method according to claim 1 wherein the laser beam has a wavelength in a range of 200 nanometers to 2 microns.
Claim 14
Dependent Claim
20 words
The method according to claim 1 wherein the pulse width is in a range of a few picoseconds to femtoseconds.
Claim 15
Dependent Claim
27 words
The method according to claim 1 wherein the breakdown includes changes caused by one or more of ionization, free electron multiplication, dielectric breakdown, plasma formation, and vaporization.
Claim 16
Dependent Claim
12 words
The method according to claim 1 wherein the breakdown includes plasma formation.
Claim 17
Dependent Claim
11 words
The method according to claim 1 wherein the breakdown includes disintegration.
Claim 18
Dependent Claim
11 words
The method according to claim 1 wherein the breakdown includes ablation.
Claim 19
Dependent Claim
11 words
The method according to claim 1 wherein the breakdown includes vaporization.
Claim 20
Dependent Claim
23 words
The method according to claim 1 wherein the spot size is varied by flexible diaphragm to a range of 1 to 100 microns.
Claim 21
Dependent Claim
34 words
The method according to claim 1 wherein a mask is placed in the path of the beam to block a portion of the beam to cause the beam to assume a desired geometric configuration.
Claim 22
Dependent Claim
13 words
The method according to claim 1 wherein the laser operating mode is non-TEMoo.
Claim 23
Dependent Claim
51 words
The method according to claim 1 wherein the laser beam defines a spot and has a lateral gaussian profile characterized in that fluence at or near the center of the beam spot it greater than the threshold fluence whereby the laser induced breakdown is ablation of an area within the spot.
Claim 24
Dependent Claim
28 words
The method according claim 22 wherein the spot size is a diffraction limited spot size providing an ablation cavity having a diameter less than the fundamental wavelength size.
Claim 25
Dependent Claim
47 words
The method according to claim 1 wherein the characteristic pulse width is obtained by determining the ablation (LIB) threshold of the material as a function of pulse width and determining where the ablation (LIB) threshold function is no longer proportional to the square root of pulse width.
Claim 26
Independent Claim
154 words
A method for laser induced breakdown of a material which comprises: a. generating a beam of one or more laser pulses in which each pulse has a pulse width equal to or less than a pulse width value corresponding to a change in slope of a curve of fluence breakdown threshold (F th ) as a function of laser pulse width (T), said change occurring at a point between first and second portions of said curve, said first portion spanning a range of relatively long pulse width where F th varies with the square root of pulse width (T 1/2 ) and said second portion spanning a range of short pulse width relative to said first portion with a F th versus T slope which differs from that of said first portion; and b. focusing said one or more pulses of said beam to a point at or beneath the surface of the material.
Claim 27
Independent Claim
154 words
A method for laser induced breakdown of a material which comprises: a. generating a beam of one or more laser pulses in which each pulse has a pulse width equal to or less than a pulse width value corresponding to a change in slope of a curve of fluence breakdown threshold (F th ) as a function of laser pulse width (T), said change occurring at a point between first and second portions of said curve, said first portion spanning a range of relatively long pulse width where F th varies with the square root of pulse width (T 1/2 ) and said second portion spanning a range of short pulse width relative to said first portion with a F th versus T slope which differs from that of said first portion; and b. focusing said one or more pulses of said beam to a point at or beneath the surface of the material.
Claim 28
Dependent Claim
45 words
The method according to claim 24 and further including: a. identifying a pulse width start point; b. focussing the laser beam initial start point at or beneath the surface of the material; and c. scanning said beam along a predetermined path in a transverse direction.
Claim 29
Dependent Claim
56 words
The method according to claim 24 and further including: a. identifying a pulse width start point; b. focussing the laser beam initial start point at or beneath the surface of the material; and c. scanning said beam along a predetermined path in a longitudinal direction in the material to a depth smaller than the Rayleigh range.
Claim 30
Dependent Claim
27 words
The method according to claim 24 wherein the breakdown includes changes caused by one or more of ionization, free electron multiplication, dielectric breakdown, plasma formation, and vaporization.
Claim 31
Dependent Claim
12 words
The method according to claim 24 wherein the breakdown includes plasma formation.
Claim 32
Dependent Claim
11 words
The method according to claim 24 wherein the breakdown includes disintegration.
Claim 33
Dependent Claim
11 words
The method according to claim 24 wherein the breakdown includes ablation.
Claim 34
Dependent Claim
11 words
The method according to claim 24 wherein the breakdown includes vaporization.
Claim 35
Independent Claim
66 words
The method according to any one of claims 1, 2, 5 or 24 wherein said beam is obtained by chirped-pulse amplification (CPA) means comprising means for generating a short optical pulse having a predetermined duration; means for stretching such optical pulse in time; means for amplifying such time-stretched optical pulse including solid state amplifying media; and means for recompressing such amplified pulse to its original duration.
Claim 36
Independent Claim
149 words
A method for laser induced breakdown (LIB) of a material with a pulsed laser beam, the material being characterized by a relationship of fluence breakdown threshold versus laser pulse width that exhibits a rapid and distinct change in slope at a predetermined laser pulse width where the onset of plasma induced breakdown occurs, said method comprising the steps of: a. generating a beam of one or more laser pulses in which each pulse has a pulse width equal to or less than said predetermined laser pulse width; and b. focusing said beam to a point at or beneath the surface of the material so that the laser beam defines a spot and has a lateral gaussian profile characterized in that fluence at or near the center of the beam spot is greater than the threshold fluence whereby the laser induced breakdown is ablation of an area within the spot.
Claim 37
Independent Claim
149 words
A method for laser induced breakdown (LIB) of a material with a pulsed laser beam, the material being characterized by a relationship of fluence breakdown threshold versus laser pulse width that exhibits a rapid and distinct change in slope at a predetermined laser pulse width where the onset of plasma induced breakdown occurs, said method comprising the steps of: a. generating a beam of one or more laser pulses in which each pulse has a pulse width equal to or less than said predetermined laser pulse width; and b. focusing said beam to a point at or beneath the surface of the material so that the laser beam defines a spot and has a lateral gaussian profile characterized in that fluence at or near the center of the beam spot is greater than the threshold fluence whereby the laser induced breakdown is ablation of an area within the spot.
Claim 38
Dependent Claim
29 words
The method according to claim 33 wherein the spot size is a diffraction limited spot size providing an ablation cavity having a diameter less than the fundamental wavelength size.
Claim 39
Independent Claim
127 words
A method for laser induced breakdown (LIB) of a material with a pulsed laser beam, the material being characterized by a relationship of fluence breakdown threshold versus laser pulse width that exhibits a rapid and distinct change in slope at a predetermined laser pulse width where the onset of plasma induced breakdown occurs, said method comprising the steps of: a. generating a beam of one or more laser pulses in which each pulse has a pulse width equal to or less than said predetermined laser pulse width; and b. focusing said beam to a point at or beneath the surface of the material which is biological tissue, the pulse width is 10 to 10,000 femtoseconds and the beam has an energy of 10 nanojoules to 1 millijoule.
Claim 40
Independent Claim
127 words
A method for laser induced breakdown (LIB) of a material with a pulsed laser beam, the material being characterized by a relationship of fluence breakdown threshold versus laser pulse width that exhibits a rapid and distinct change in slope at a predetermined laser pulse width where the onset of plasma induced breakdown occurs, said method comprising the steps of: a. generating a beam of one or more laser pulses in which each pulse has a pulse width equal to or less than said predetermined laser pulse width; and b. focusing said beam to a point at or beneath the surface of the material which is biological tissue, the pulse width is 10 to 10,000 femtoseconds and the beam has an energy of 10 nanojoules to 1 millijoule.
Claim 41
Independent Claim
142 words
A method for laser Induced breakdown (LIB) of a material by plasma formation with a pulsed laser beam, the material being characterized by a relationship of fluence breakdown threshold versus laser pulse width that exhibits a distinct change in slope at a characteristic laser pulse width, said method comprising the steps of: a. generating a beam of one or more laser pulses in which each pulse has a pulse width equal to or less than said characteristic laser pulse width, said characteristic pulse width being defined by the ablation (LIB) threshold of the material as a function of pulse width where the ablation (LIB) threshold function is no longer proportional to the square root of pulse width; and b. focusing said beam to a point at or beneath the surface of the material and inducing breakdown by plasma formation in the material.
Claim 42
Independent Claim
142 words
A method for laser Induced breakdown (LIB) of a material by plasma formation with a pulsed laser beam, the material being characterized by a relationship of fluence breakdown threshold versus laser pulse width that exhibits a distinct change in slope at a characteristic laser pulse width, said method comprising the steps of: a. generating a beam of one or more laser pulses in which each pulse has a pulse width equal to or less than said characteristic laser pulse width, said characteristic pulse width being defined by the ablation (LIB) threshold of the material as a function of pulse width where the ablation (LIB) threshold function is no longer proportional to the square root of pulse width; and b. focusing said beam to a point at or beneath the surface of the material and inducing breakdown by plasma formation in the material.
Claim 43
Independent Claim
115 words
A method for laser induced breakdown of a material which comprises: a. determining, for a selected material, a characteristic curve of fluence breakdown threshold (F th ) as a function of laser pulse width; b. identifying a pulse width value on said curve corresponding to a rapid and distinct change in slope of said F th versus pulse width curve characteristic of said material; c. generating a beam of one or more laser pulses, said having a pulse width at or below said pulse width value corresponding to said distinct change in slope; and d. focusing said one or more pulses of said beam to a point at or beneath the surface of the material.
Claim 44
Independent Claim
115 words
A method for laser induced breakdown of a material which comprises: a. determining, for a selected material, a characteristic curve of fluence breakdown threshold (F th ) as a function of laser pulse width; b. identifying a pulse width value on said curve corresponding to a rapid and distinct change in slope of said F th versus pulse width curve characteristic of said material; c. generating a beam of one or more laser pulses, said having a pulse width at or below said pulse width value corresponding to said distinct change in slope; and d. focusing said one or more pulses of said beam to a point at or beneath the surface of the material.
Claim 45
Dependent Claim
45 words
The method according to claim 37 and further including: a. identifying a pulse width start point; b. focusing the laser beam initial start point at or beneath the surface of the material; and c. scanning said beam along a predetermined path in a transverse direction.
Claim 46
Dependent Claim
56 words
The method according to claim 37 and further including: a. identifying a pulse width start point; b. focusing the laser beam initial start point at or beneath the surface of the material; and c. scanning said beam along a predetermined path in a longitudinal direction in the material to a depth smaller than the Rayleigh range.
Claim 47
Dependent Claim
27 words
The method according to claim 37 wherein the breakdown includes changes caused by one or more of ionization, free electron multiplication, dielectric breakdown, plasma formation, and vaporization.
Claim 48
Dependent Claim
12 words
The method according to claim 37 wherein the breakdown includes plasma formation.
Claim 49
Dependent Claim
11 words
The method according to claim 37 wherein the breakdown includes disintegration.
Claim 50
Dependent Claim
11 words
The method according to claim 37 wherein the breakdown include ablation.
Claim 51
Dependent Claim
10 words
The method according to claim 37 wherein breakdown includes vaporization.
Claim 52
Independent Claim
64 words
The method according to any one of claims 35, or 37 wherein said beam is obtained by chirped-pulse amplification (CPA) means comprising means for generating a short optical pulse having a predetermined duration; means for stretching such optical pulse in time; means for amplifying such time-stretched optical pulse including solid state amplifying media; and means for recompressing such amplified pulse to its original duration.
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 2000-08-11 | 2001-02-10 | 2001-08-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-08-11 | 2005-02-10 | 2005-08-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-08-11 | 2009-02-10 | 2009-08-12 | $7700.00 | Window Closed / Lapsed |