Laser amplification system

• US 8,861,075 B2
• Filed: 02/26/2010
• Issued: 10/14/2014
• Est. Priority Date: 03/05/2009
• Status: Active Grant

• Current Assignee: The Board of Trustees of Michigan State University (Michigan State University)
• Original Assignee: The Board of Trustees of Michigan State University (Michigan State University)
• Inventors: Dantus, Marcos, Lozovoy, Vadim V.
• Primary Examiner(s): BOLDA, ERIC L
• Application Number:
  US13/254,884
• Publication Number:
  US 20120076504A1
• Time in Patent Office: 1,691 Days
• Field of Search: 372/25, 359/337, 359/337.5
• US Class Current: 359/337.5
• CPC Class Codes: H01S 3/005 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 Class Codes: H01S 3/0057 Temporal shaping, e.g. pulse compression, frequency chirping soliton generation and propagation G02F1/3513, H01S3/063 and H01S3/108
• CPC Class Codes: H01S 3/23 Arrangements of two or more lasers not provided for in groups H01S3/02 - H01S3/22, e.g. tandem arrangements of separate active media

Abstract

A high peak intensity laser amplification system and the method therein implemented are provided. In a first aspect of the invention, the laser system includes at least one optical member (27) operably introducing a phase function into a high peak intensity laser pulse (25). A further aspect includes introducing destructive interference in an unchirped laser pulse prior to amplification and reconstructive interference in the output laser pulse after amplification. Dynamic pulse shaping is employed in another aspect of the present invention.

Claims

1. A method of using a laser, the method comprising:

(a) emitting a high peak intensity laser beam pulse;

(b) introducing at least one minimal correlation phase function into the high peak intensity pulse spanning a spectrum of the pulse without symmetry; and

(c) amplifying the pulse substantially without pre-chirping and without damage to an amplifier.

2. The method of claim 1, further comprising introducing a substantially identical phase function into the pulse after the amplification step to cancel the effects of the phase function originally introduced in the pulse before the amplification.

3. The method of claim 1, further comprising using a pulse shaper at a Fourier Plane to introduce the phase function prior to the amplification.

4. The method of claim 1, further comprising using binary phase shaping to introduce the phase function.

5. The method of claim 1, further comprising using at least 100 bits in a binary series of the minimal correlation phase function to deter nonlinear optical processes from being created by the pulse which would otherwise damage the amplifier.

6. The method of claim 1, further comprising transmitting the amplified high peak intensity pulse through an optical fiber.

7. The method of claim 1, further comprising encoding a communications signal into the pulse prior to the amplification.

8. The method of claim 1, further comprising sending the pulse between an oscillator and an output of the amplifier, wherein the requirement for chirping the input pulse is reduced by at least two orders of magnitude.

9. The method of claim 1, further comprising using a double pass optical path so the same pulse shaper interacts with the pulse before and after amplification.

10. The method of claim 1, further comprising using pulse shaping to break the single high intensity pulse into multiple less intense pulses prior to the amplification.

11. The method of claim 1, further comprising using pulse shaping to deter second or higher nonlinear optical processes induced by the pulse through introduction of a phase that causes destructive nonlinear optical interference in a calculated manner, without use of a genetic learning algorithm, prior to the amplification.

12. The method of claim 1, further comprising using an optical member to compensate for high order dispersion and self-phase modulation in a fiber amplifier.

13. A method of using a laser, the method comprising:

(a) shaping a high peak intensity laser beam pulse, which is substantially unchirped, with a minimal correlation binary phase function without symmetry;

(b) amplifying the pulse after step (a); and

(c) shaping the amplified pulse with a substantially identical minimal correlation binary phase function.

14. The method of claim 13, wherein the amplifying of the high peak intensity pulse is conducted with chirping requirements that are reduced by at least two orders of magnitude and without damage to an amplifier.

15. The method of claim 13, further comprising using the prior minimal correlation binary phase function to prevent nonlinear optical processes from being created in the pulse which would otherwise damage the amplifier.

16. The method of claim 13, further comprising transmitting the amplified high peak intensity pulse through an optical fiber.

17. The method of claim 13, further comprising sending the pulse between an oscillator and an output of the amplifier without passing through a linear chirp stretcher or compressor.

18. The method of claim 13, further comprising using a double pass optical path for the pulse wherein the pulse follows a first direction through a pulse shaper, through an amplifier and to a reflective optic, and then reverses to follow a second and substantially opposite direction back through the amplifier and pulse shaper.

19. The method of claim 13, further comprising using pulse shaping to break the single high intensity pulse into multiple less intense pulses prior to the amplification.

20. The method of claim 13, further comprising using pulse shaping to deter second or higher order nonlinear optical processes by the pulse through destructive interference in a predetermined manner, without use of a genetic learning algorithm, prior to the amplification.

21. The method of claim 13, further comprising emitting the pulse from a fiber oscillator and amplifying the pulse with a fiber amplifier.

22. A laser system comprising:

a laser oscillator emitting a high peak intensity laser pulse;

at least one optical member introducing a phase function into the high peak intensity laser pulse to suppress nonlinear optical processes in the pulse; and

an amplifier amplifying the high peak intensity laser pulse which is substantially unchirped prior to the amplification, the amplifier being located downstream of the optical member;

the at least one optical member introducing the same phase function to the high peak intensity laser pulse after amplification.

23. The laser system of claim 22, wherein the at least one optical member includes a single pulse shaper.

24. The laser system of claim 22, wherein the at least one optical member includes two pulse shapers, one located before the amplifier and the other located after the amplifier.

25. The laser system of claim 22, wherein the at least one optical member includes a optimally bent mirror and a phase mask located adjacent each other.

26. The laser system of claim 22, wherein the phase function is a minimal correlation binary phase function applied on a spectrum of the pulse without symmetry.

27. The laser system of claim 22, wherein the at least one optical member separates the high intensity pulse into multiple less intense pulses prior to the amplification.

28. The laser system of claim 22, further comprising:

a reflective member located downstream of the amplifier;

the at least one optical member, the amplifier and the reflective member being arranged in a double pass manner wherein the pulse interacts with the same at least one optical member before and after it passes through the amplifier.

29. The laser system of claim 22, further comprising an optical fiber transmitting the amplified pulse and a communications receiver operably receiving the pulse from the optical fiber to decode a communications signal carried in the pulse.

30. The laser system of claim 22, wherein the pulse is substantially unchirped and is sent from the oscillator to the amplifier without the addition of positive or negative chirp through a stretcher or compressor, but the substantially unchirped high intensity laser pulse does not damage the amplifier.

31. A laser system comprising:

a substantially unchirped laser pulse having a duration of less than 10picoseconds;

at least one pulse shaper introducing a minimal correlation binary phase function into the pulse; and

an amplifier amplifying the unchirped pulse after the introduction of the phase function;

the at least one pulse shaper neutralizing the minimal correlation binary phase function of the unchirped pulse after the amplification.

32. The laser system of claim 31, wherein the at least one pulse shaper includes a mirror and a phase mask having binary depressions therein.

33. The laser system of claim 31, wherein the at least one pulse shaper changes the pulse into multiple less intense sub-pulses prior to the amplification.

34. The laser system of claim 31, further comprising:

a reflective member located downstream of the amplifier;

the at least one pulse shaper, the amplifier and the reflective member being arranged in a double pass manner wherein the pulse interacts with the same at least one pulse shaper before and after it passes through the amplifier.

35. The laser system of claim 31, further comprising an optical fiber transmitting the amplified pulse and a communications receiver operably receiving the pulse from the optical fiber to decode a communications signal carried in the pulse.

36. The laser system of claim 31, wherein the substantially unchirped pulse is sent from an oscillator to the amplifier without passing through a stretcher or compressor, the substantially unchirped pulse has an intensity of at least 1 kW, but does not damage the amplifier due to the minimal correlation binary phase function effects in the pulse without symmetry.