Laser effects and laser devices

• US 7,173,949 B2
• Filed: 12/01/2000
• Issued: 02/06/2007
• Est. Priority Date: 12/03/1999
• Status: Expired due to Fees

• Current Assignee: Qinetiq Limited (QinetiQ Group PLC)
• Original Assignee: Qinetiq Limited (QinetiQ Group PLC)
• Inventors: Cook, Gary
• Primary Examiner(s): Harvey; Minsun Oh
• Assistant Examiner(s): Flores-Ruiz; Delma R.
• Application Number:
  US10/148,681
• Publication Number:
  US 20040213300A1
• Time in Patent Office: 2,258 Days
• Field of Search: 372/3, 372/92, 372/6
• US Class Current: 372/3
• CPC Class Codes: G02F 1/39 for parametric generation or amplification of light, infrared or ultraviolet waves
• CPC Class Codes: H01S 3/06716 Fibre compositions per se C03C13/04or doping with active elements lasing materials in general H01S3/14
• CPC Class Codes: H01S 3/08086 Multiple-wavelength emission
• CPC Class Codes: H01S 3/30 using scattering effects, e.g. stimulated Brillouin or Raman effects
• CPC Class Codes: H01S 3/302 in an optical fibre

Abstract

A glass fiber (22) has a core (24) provided with Raman laser effect particles (28) embedded in a glass matrix (30), with glass cladding (26) around the core. The refractive index of the glass matrix (30) is matched to that of the Raman laser effect particles (28) so as to avoid scattering. It is not necessary to have a single crystal of Raman laser material to create a laser effect in the glass fiber. A length of fiber in the order of meters or tens of meters can produce optical laser light. It is possible to have a single fiber (22) emit laser light at different frequencies due to Stokes and Anti-Stokes emissions. A simple laser device can therefore produce several colors of laser beams.

Claims

1. A Raman device comprising:

couplant material and

a plurality of regions of photon-emitting Raman material, each of said

plurality of regions of photon-emitting Raman material producing at least one of Strokes radiation and anti-Stokes radiation, wherein

plurality of regions of photon-emitting Raman material are embedded within said couplant material.

2. A device according to claim 1 wherein said Raman device is a continuous wave Raman laser device.

3. A device according to claim 1 in which said couplant material is glass.

4. A device according to claim 1 wherein said Raman device is an optical parametric oscillator and at least one of said plurality of regions of photon-emitting Raman material comprises parametric oscillator material.

5. A device according to claim 1 wherein the refractive index of said plurality of regions of photon-emitting Raman material and the refractive index of said couplant material are substantially matched over the wavelength range 500–

700 nm.

6. A device according to claim 1 and further comprising a temperature controller to control the temperature of said plurality of regions of photon-emitting Raman material and said couplant material.

7. An optical fibre comprising a core region surrounded by a cladding region, wherein said core region comprises a Raman device according to claim 1.

8. A device according to claim 1, wherein said couplant material and said plurality of regions of photon-emitting Raman material are formed as a non-fibrous bulk solid.

9. A device according to claim 1 wherein said Raman device is a Raman laser device and said plurality of regions of photon-emitting Raman material are arranged such that said Raman laser device emits two or more different colours of laser light.

10. A device according to claim 9 wherein said two or more different colours of laser light comprise at least two of the colours red, orange, yellow, green and blue.

11. A device according to claim 9 and further comprising a pump laser, wherein a matrix body is formed by said couplant material and said plurality of regions of photon-emitting Raman material and said matrix body has a length such that said at least two different colours of laser light can be emitted by said device.

12. A device according to claim 9 wherein light produced from a first Raman emission from said photon emitting Raman material drives a second Raman emission from said photon emitting Raman material such that said device emits said two or more different colours of laser light.

13. A device according to claim 1 wherein said plurality of regions of photon-emitting Raman material comprise at least one first region and at least one second region, wherein said at least one first region comprises photon-emitting Raman material of a first kind and said at least one second region comprises photon-emitting Raman material of a second kind.

14. A device according to claim 1 wherein said couplant material is adapted to emit radiation of a first wavelength and said plurality of regions of photon-emitting Raman material are adapted to emit radiation of a different wavelength.

15. A device according to claim 14, wherein the emission of radiation from said couplant material is adapted to cause the emission of radiation from said plurality of regions of photon-emitting Raman material.

16. A device according to claim 14 and further comprising a laser pump source, wherein said couplant material is adapted to produce radiation of a first wavelength when driven by said laser pump source, and said plurality of regions of photon-emitting Raman material regions are arranged to change the wavelength of at least some of said radiation of a first wavelength.

17. A device according to claim 1 wherein said Raman device is a Raman photonic bandgap device.

29. A device according to claim 1 in which said couplant material is a polymer.

30. A device according to claim 14, wherein the emission of radiation from said plurality of regions of photon-emitting Raman material is adapted to cause the emission of radiation from said couplant material.

31. A device according to claim 1 wherein said Raman device is a Raman photonic crystal device.

32. A device according to claim 1 wherein said Raman device is a Raman detector device.

33. A device according to claim 1 wherein said Raman device is a Raman sensor device.

18. A method of producing laser radiation comprising the steps of;

(i) taking at least one laser body comprising a plurality of Raman laser material regions embedded within a couplant material, and

(ii) introducing laser light into said at least one laser body to cause Raman effect emission form the Raman laser material region.

19. A method according to claim 18 and further comprising the step of shortening the length of said at least one laser body to a desired length chosen such that the Raman radiation emitted comprises at least one desired wavelength.

20. A method according to claim 18 wherein said Raman effect emission comprises at least two of the following types of emission:

first Stokes emission;

second Stokes emission;

third Stokes emission;

fourth Stokes emission;

subsequent Stokes emissions;

first Anti-Stokes emission;

subsequent Anti-Stokes emissions.

21. A method according to claim 18 wherein said step of taking at least one laser body comprises taking a laser body that comprises at least two kinds of Raman laser material and producing therefrom at least two different wavelengths of laser light.

22. A method according to claim 18 wherein the step of taking at least one laser body comprises taking at least two laser bodies of similar composition but of different effective lengths such that different wavelength Raman effect radiation is emitted.

23. A method of manufacturing a laser device comprising the step of adding Raman laser material to a couplant material.

24. A method according to claim 23 in which the step of adding Raman laser material to a couplant material comprises mixing particle of Raman laser material with said couplant material.

25. A method according to claim 23 in which the step of adding Raman laser material to a couplant material comprises the steps of (a) dissolving Raman laser material in said couplant material and (b) crystallising out said Raman laser material such that crystals of Raman laser material are formed in said couplant material.

26. A method of manufacturing an optical parametric oscillator device comprising the step of adding optical parametric Raman material to a couplant material.

27. A method according to claim 26 in which the step of adding optical parametric Raman material to a couplant material comprises mixing particle of optical parametric Raman material with said couplant material.

28. A method according to claim 26 in which the step of adding optical parametric Raman material to a couplant material comprises the steps of (a) dissolving optical parametric Raman material in said couplant material and (b) crystallising out said optical parametric Raman material such that crystals of optical parametric Raman material are formed in said couplant material.