Laser systems and methods

Patent metadata

Field	Value
Publication number	US-10840666-B2
Application number	US-201816008438-A
Country	US
Kind code	B2
Filing date	Jun 14, 2018
Priority date	Jun 20, 2017
Publication date	Nov 17, 2020
Grant date	Nov 17, 2020

Abstract

Laser systems and methods are disclosed. One laser system comprises: a plurality of laser resonators, each resonator being operable to discharge an input laser beam; a relay assembly including at least one curved reflective surface that redirects each input laser beam, and reduces a beam size of the redirected beam; a galvo including a curved reflective surface that receives each redirected beam, and outputs a combined laser beam at power level greater than a power level of each laser input beam; and a coupling assembly that reduces spherical aberrations in the combined laser beam, and directs the combined laser beam into an optical fiber. In this system, the combined laser beam may have a maximum beam parameter product lower than a minimum beam parameter product of the optical fiber. Related systems and methods are also disclosed.

First claim

The invention claimed is:

1. A laser system comprising:
a plurality of laser resonators, each resonator being operable to discharge an input laser beam;
a relay assembly including at least one curved reflective surface that redirects each input laser beam, and reduces a beam size of the redirected beam;
a galvo including a curved reflective surface that receives each redirected beam, and outputs a combined laser beam at power level greater than a power level of each laser input beam; and
a coupling assembly that reduces spherical aberrations in the combined laser beam, and directs the combined laser beam into an optical fiber,
wherein the combined laser beam has a maximum beam parameter product lower than a minimum beam parameter product of the optical fiber, and
wherein the at least one curved reflective surface of the relay assembly has a first curvature radius, the curved reflective surface of the galvo has a second curvature radius, and the first curvature radius is approximately one third the second curvature radius.

2. The laser system of claim 1 , wherein the second curvature radius reduces spherical aberrations in the combined laser beam.

3. The laser system of claim 1 , wherein:
each input laser beam is discharged along a beam path comprising: (i) a first distance extending from one resonator of the plurality of laser resonators to the at least one curved reflective surface of the relay assembly; (ii) a second distance extending from the at least one curved reflective surface of the relay assembly to the reflective surface of the galvo; and (iii) a third distance extending from the reflective surface of the galvo to an optical fiber; and
the first and second curvature radii are sized relative to the first, second, and third distances.

4. The laser system of claim 3 , wherein the first distance is approximately equal to the second distance, and the third distance is greater than the sum of the first and second distances.

5. The laser system of claim 1 , further comprising additional optical components located between the galvo and the coupling assembly, the additional optical components including at least one of: a beam splitter; a beam combiner; a shutter; or a black shield.

6. The laser system of claim 1 , wherein the coupling assembly outputs the combined laser beam onto an input surface of the optical fiber, and the beam parameter product of the combined laser beam is at least 10% less than a beam parameter product of the optical fiber at the input surface.

7. The laser system of claim 1 , wherein the coupling assembly comprises one aspherical lens or two spherical lenses.

8. The laser system of claim 1 , wherein the at least one curved reflective surface is mounted to a surface.

9. The laser system of claim 8 , wherein the at least one curved reflective surface is mounted to a surface via a tilt mount, wherein the tilt mount is movable in at least two degrees of freedom relative to the surface.

10. The laser system of claim 1 , wherein:
the relay assembly further comprises a second curved reflective surface;
the at least one curved reflective surface redirects the input laser beam towards the second curved reflective surface; and
the second curved reflective surface redirects the input laser beam towards a reflective surface of the galvo.

11. The laser system of claim 10 , wherein:
each input laser beam is discharged along a beam path comprising: (i) a first distance extending from one resonator of the plurality of laser resonators to the at least one curved reflective surface of the relay assembly; (ii) a second distance extending from the at least one curved reflective surface of the relay assembly to the second curved reflective surface; (iii) a third distance extending between the second curved reflective surface and the reflective surface of the galvo; and (iv) a fourth distance extending from the reflective surface of the galvo to an optical fiber; and
the first and second curvature radii are sized relative to the first, second, third, and fourth distances.

12. The laser system of claim 11 , wherein the fourth distance is greater than the sum of the first, second, and third distances.

13. A method comprising:
discharging input laser beams from a plurality of laser generators;
directing each input laser beam towards a relay assembly including at least one curved reflective surface that reduces a beam size of the input laser beam, and redirects the beam toward a reflective surface of a galvo;
combining the input laser beams, with the reflective surface of the galvo, into a combined laser beam having a power level greater than a power level of each input laser beam, and
outputting the combined laser beam to an optical fiber,
wherein the combined laser beam has a maximum beam parameter product lower than a minimum beam parameter product of the optical fiber, and
wherein each input laser beam is discharged along a beam path comprising: (i) a first distance extending from one resonator of the plurality of laser resonators to the at least one curved reflective surface of the relay assembly; (ii) a second distance extending from the at least one curved reflective surface of the relay assembly to the reflective surface of the galvo; and (iii) a third distance extending from the reflective surface of the galvo to the optical fiber, and the first distance is approximately equal to the second distance.

14. The method of claim 13 , wherein the reflective surface of the galvo is curved, and the method further comprises reducing spherical aberrations in the combined laser beam.

15. The method of claim 13 , further comprising rotating the reflective surface of the galvo to output the combined laser beam at a power level greater than a power level of each input laser beam.

16. The method of claim 13 , further comprising aligning the plurality of laser resonators with the at least one curved reflective surface to direct each input laser beam towards the relay assembly.

17. The method of claim 13 , wherein the combined laser beam is outputted onto an input surface of the optical fiber, and the beam parameter product of the combined laser beam is at least 10% less than a beam parameter product of the optical fiber at the input surface.

18. A laser system comprising:
a plurality of laser resonators, each resonator being operable to discharge an input laser beam;
a relay assembly including at least one curved reflective surface that redirects each input laser beam, and reduces a beam size of the redirected beam;
a galvo including a curved reflective surface that receives each redirected beam, and outputs a combined laser beam at power level greater than a power level of each laser input beam; and
a coupling assembly that reduces spherical aberrations in the combined laser beam, and directs the combined laser beam into an optical fiber,
wherein the at least one curved reflective surface of the relay assembly has a first curvature radius, the curved reflective surface of the galvo has a second curvature radius, and the first curvature radius is approximately one third the second curvature radius, and
wherein each input laser beam is discharged along a beam path comprising: (i) a first distance extending from one resonator of the plurality of laser resonators to the at least one curved reflective surface of the relay assembly; (ii) a second distance extending from the at least one curved reflective surface of the relay assembly to the reflective surface of the galvo; and (iii) a third distance extending from the reflective surface of the g

Assignees

• Boston Scient Scimed Inc

Inventors

• Yu Honggang

Classifications

• A61B18/26

  for producing a shock wave, e.g. laser lithotripsy · CPC title

• H01S3/0085

  Modulating the output, i.e. the laser beam is modulated outside the laser cavity · CPC title

• G02B6/4214

  the intermediate optical element having redirecting reflective means, e.g. mirrors, prisms for deflecting the radiation from horizontal to down- or upward direction toward a device (G02B6/4246 takes precedence) · CPC title

• H01S3/005

  Optical devices external to the laser cavity, specially adapted for lasers, e.g. for homogenisation of the beam or for manipulating laser pulses, e.g. pulse shaping (shaping laser beam for working metal or other materials B23K26/06; optical elements, systems or apparatus in general G02B) · CPC title

• G02B6/4206

  Optical features (G02B6/4207, G02B6/421 take precedence) · CPC title