Apparatus for ultrashort pulse transportation and delivery

• US 6,272,156 B1
• Filed: 01/12/1999
• Issued: 08/07/2001
• Est. Priority Date: 01/28/1998
• Status: Expired due to Fees

• Current Assignee: Coherent Inc (Coherent Corp.)
• Original Assignee: Coherent Inc (Coherent Corp.)
• Inventors: Reed, Murray K., Atherton, Briggs
• Primary Examiner(s): Scott, Jr., Leon
• Application Number:
  US09/229,456
• Time in Patent Office: 938 Days
• Field of Search: 372/25, 372/102, 372/6
• US Class Current: 372/25
• CPC Class Codes: H01S 3/0057 Temporal shaping, e.g. pulse compression, frequency chirping soliton generation and propagation G02F1/3513, H01S3/063 and H01S3/108

Abstract

Apparatus for transporting a laser-pulse from a pulsed-laser to a receiver includes a pulse-expander, an optical-fiber, and a pulse-compressor. The pulse-expander is arranged to receive and temporally-expand the laser-pulse from the pulsed laser. The optical-fiber at its proximal end to receive the laser-pulse from the pulse-expander and transport the laser-pulse to the pulse-compressor. The pulse-compressor is arranged to receive the laser-pulse from the optical-fiber, temporally-compress the laser-pulse, and deliver the laser-pulse to the receiver. The pulse-compressor includes a block of optically-dispersive material, the temporal-compression being effected by an optical arrangement that causes the laser-pulse to follow a zigzag path through the block of optically-dispersive material. The pulse-expander may be arranged to provide variable third-order dispersion of a laser-pulse being expanded. The pulse compressor may be included in a handpiece attached to the distal end of the optical-fiber.

Claims

1. Apparatus for transporting a laser-pulse from a pulsed-laser to a receiver, comprising:

a pulse-expander, an optical-fiber, and a pulse-compressor;

said pulse-expander arranged to receive and temporally expand the laser-pulse from the pulsed laser;

said optical-fiber positioned to receive the laser-pulse from said pulse-expander and transport the pulse to said pulse-compressor, said pulse becoming temporally-compressed as a result of said transporting;

said pulse-compressor including a block of optically-dispersive material through which the laser-pulse from the optical-fiber passes, said block further temporally-compresses the laser-pulse and delivers the laser-pulse to the receiver, and

wherein said pulse-compressor includes an optical arrangement that causes the laser-pulse to follow a zigzag path through said block of optically-dispersive material such that the net dispersion for a given length of the optically-dispersive material is increased.

2. The apparatus of claim 1, wherein said pulse expander, said optical-fiber and said block are selected to minimize the difference between the amount of temporal expansion created by the pulse-expander and the combined amount of temporal compression created by the optical-fiber and the pulse-compressor.

3. The apparatus of claim 1, wherein said pulse-expander causes second and third-order dispersion of said laser pulse and said third-order dispersion is variable.

4. The apparatus of claim 3, wherein said pulse-expander includes a diffraction-grating and a refractive optical-component and is arranged such that the received laser-pulse is diffracted by the diffraction-grating and traverses said refractive optical-component before being delivered to said optical-fiber, said refractive optical-component being moveable with respect to said diffraction-grating for varying said third-order dispersion.

5. The apparatus of claim 4, wherein said movement of said refractive optical-component with respect to said diffraction-grating causes a change in path length of the laser-pulse through said refractive optical-component.

6. The apparatus of claim 3, wherein said pulse-expander includes a diffraction-grating having a diffraction plane and a refractive optical-component having an optical axis and is arranged such that the received laser-pulse is diffracted at least once by the diffraction-grating and traverses said refractive optical-component at least once before being delivered to said optical-fiber, said refractive optical-component being rotatable about a rotation-axis transverse to said optical-axis for varying said third-order dispersion.

7. The apparatus of claim 6, wherein said received laser-pulse is diffracted a plurality of times by said diffraction-grating and traverses said refractive optical-component a plurality of times before being delivered to said optical-fiber.

8. The apparatus of claim 7, wherein said received laser-pulse is diffracted four times and traverses said refractive optical-component four times.

9. The apparatus of claim 1, wherein said pulse-compressor includes first and second mirrors facing respectively first and second opposite faces of said block of optically-dispersive material, said zigzag path of the laser-pulse through said block of optically-dispersive material being caused by multiple reflections of the laser-pulse between said first and second mirrors.

10. The apparatus of claim 1, wherein said block of optically-dispersive material of said pulse-compressor has first and second opposite faces each thereof having a reflective portion, said zigzag path of the laser-pulse through said block of optically-dispersive material being caused by multiple reflections of the laser-pulse between said reflective portions of said first and second opposite faces.

11. The apparatus of claim 1, wherein said block of optically-dispersive material of said pulse-compressor has first and second opposite end-faces, and first and second opposite lateral-faces, said end-faces and lateral-faces arranged such that said zigzag path of the laser-pulse through said block of optically-dispersive material is caused by refraction of the laser pulse at said first end-face followed by multiple total-internal-reflections between said first and second lateral-faces.

12. The apparatus of claim 11 wherein said laser pulse exits said block of optically-dispersive material via said second end-face.

13. The apparatus of claim 1, wherein said pulse-compressor is located in a handpiece connected to said optical-fiber.

14. Apparatus for transporting a laser-pulse from a pulsed-laser to a receiver, comprising:

a pulse-expander, an optical-fiber, and a pulse-compressor;

said pulse-expander arranged to receive and temporally expand the laser-pulse from the pulsed laser, said pulse-expander including an optical element that is movable to adjust the amount of said temporal expansion by said pulse-expander;

said optical-fiber positioned to receive the laser-pulse from said pulse-expander and transport the pulse to said pulse-compressor, said pulse becoming temporally-compressed as a result of said transporting; and

said pulse-compressor arranged to receive the laser-pulse from said optical fiber, and further temporally-compresses the laser-pulse and delivers the laser-pulse to the receiver.

15. The apparatus of claim 14, wherein said pulse expander, said optical-fiber and said pulse compressor are selected to minimize the difference between the amount of temporal expansion created by the pulse-expander and the combined amount of temporal compression created by the optical-fiber and the pulse-compressor.

16. The apparatus of claim 15, wherein said movable optical element is a refractive optical-component.

17. The apparatus of claim 16, wherein said refractive optical-component is rotated or translated with respect to said diffraction-grating for varying third-order dispersion.

18. The apparatus of claim 17, wherein said pulse-expander causes second and third-order dispersion of said laser pulse and said third-order dispersion is variable.

19. The apparatus of claim 17, wherein said movement of said refractive optical-component with respect to said diffraction-grating causes a change in path length of the laser-pulse through said refractive optical-component.

20. The apparatus of claim 15, wherein said pulse-expander further includes a diffraction-grating, and wherein the grating and optical component are arranged such that the received laser-pulse is diffracted by the diffraction-grating and traverses said refractive optical-component before being delivered to said optical-fiber.

21. The apparatus of claim 15, wherein the pulse-compressor includes:

a block of optically-dispersive material through which the laser-pulse from the optical-fiber passes; and

an optical arrangement that causes the laser-pulse to follow a zigzag path through said block of optically-dispersive material.

22. The apparatus of claim 21, wherein said pulse-compressor includes first and second mirrors facing respectively first and second opposite faces of said block of optically-dispersive material, said zigzag path of the laser-pulse through said block of optically-dispersive material being caused by multiple reflections of the laser-pulse between said first and second mirrors.

23. The apparatus of claim 21, wherein said block of optically-dispersive material of said pulse-compressor has first and second opposite faces each thereof having a reflective portion, said zigzag path of the laser-pulse through said block of optically-dispersive material being caused by multiple reflections of the laser-pulse between said reflective portions of said first and second opposite faces.

24. The apparatus of claim 21, wherein said block of optically-dispersive material of said pulse-compressor has first and second opposite end-faces, and first and second opposite lateral-faces, said end-faces and lateral-faces arranged such that said zigzag path of the laser-pulse through said block of optically-dispersive material is caused by refraction of the laser pulse at said first end-face followed by multiple total-internal-reflections between said first and second lateral-faces.

25. The apparatus of claim 24 wherein said laser pulse exits said block of optically-dispersive material via said second end-face.

26. The apparatus of claim 15, wherein said pulse-expander includes a diffraction-grating having a diffraction plane and said movable optical element is a refractive optical-component having an optical axis, and wherein the grating and the optical component are arranged such that the received laser-pulse is diffracted at least once by the diffraction-grating and traverses said refractive optical-component at least once before being delivered to said optical-fiber, said refractive optical-component being rotatable about a rotation-axis transverse to said optical-axis for varying said third-order dispersion.

27. The apparatus of claim 26, wherein said received laser-pulse is diffracted a plurality of times by said diffraction-grating and traverses said refractive optical-component a plurality of times before being delivered to said optical-fiber.

28. The apparatus of claim 27, wherein said received laser-pulse is diffracted four times and traverses said refractive optical-component four times.

29. The apparatus of claim 15 wherein said pulse-compressor is located in a handpiece connected to said optical-fiber.

30. A handpiece for directing ultrafast laser-pulses transported by an optical fiber toward a target, the optical-fiber being arranged such that the transported laser pulses exit the optical-fiber at an exit end thereof, the handpiece comprising:

a connection to the exit end of the optical-fiber; and

a block of optically-dispersive material and arranged such that a pulse exiting the optical fiber traverses said block of optically-dispersive material before being directed toward the target, said traversal of said block of optically dispersive material causing temporal compression of the pulse.

31. The handpiece of claim 30, further comprising:

an optical arrangement that causes the laser-pulse to follow a zigzag path through said block of optically-dispersive material.