IPC분류정보
국가/구분 |
United States(US) Patent
공개
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0297510
(2003-06-02)
|
공개번호 |
US-0028091
(2004-02-12)
|
우선권정보 |
DE-0030259 (2000-06-20) |
국제출원번호 |
PCT/EP01/06610
(2001-06-12)
|
발명자
/ 주소 |
- Baev, Valeri
- Stark, Arnold
- Salewski, Stefan
- Thurau, Wolfgang
- Toschek, Peter
|
대리인 / 주소 |
|
인용정보 |
피인용 횟수 :
0 인용 특허 :
0 |
초록
▼
A fiber laser with a fiber (16) for laser light generation having an entrance end (14) and an exit end (20) comprises a pump light source (10) for generating pump light to be coupled via the entrance side (14) into the fiber (16). At the exit end of the fiber (16) a first resonator mirror (26) is pr
A fiber laser with a fiber (16) for laser light generation having an entrance end (14) and an exit end (20) comprises a pump light source (10) for generating pump light to be coupled via the entrance side (14) into the fiber (16). At the exit end of the fiber (16) a first resonator mirror (26) is provided which is highly reflecting for the laser light to be generated in the wavelength range with the smallest light amplification and to the light of the pump light source (10). Spaced from the first resonator mirror (26) a second resonator mirror (28) is provided via which light of further wavelength ranges can be fed back into the fiber (16) with the aid of a collimating lens (30).
대표청구항
▼
1. Fiber laser, comprising:a fiber (16) for laser light generation having an entrance end (14) and an exit end (20), a pump light source (10) for generating pump light provided to be coupled via the entrance end (14) into the fiber (16), and a resonator unit (26,28) provided at the exit end (20) of
1. Fiber laser, comprising:a fiber (16) for laser light generation having an entrance end (14) and an exit end (20), a pump light source (10) for generating pump light provided to be coupled via the entrance end (14) into the fiber (16), and a resonator unit (26,28) provided at the exit end (20) of the fiber, characterized in that the resonator unit comprises a first resonator mirror (26) connected with the exit end (20), and a second resonator mirror (28) arranged in spaced relationship to the exit end (20), said second resonator mirror (28) being adapted for feeding light of at least one wavelength range emerging at the exit end (20) back into the fiber. 2. Fiber laser according to claim 1, characterized in that the first resonator mirror (26) is highly reflecting for the laser light to be generated, namely in the wavelength range with the smallest light amplification, offering in particular a reflectivity of 50%-99.9%, preferably 80%-99.1%, such that 0.1%-50%, preferably 0.9%-20%, of the generated laser light in this wavelength range are coupled out. 3. Fiber laser according to claim 1 or2, characterized in that the first resonator mirror (26) is highly reflecting for the wavelength range of the pump light, offering in particular a reflectivity of more than 50%, in a particularly preferred aspect of more than 75%. 4. Fiber laser according to one of claims1-3, characterized in that an air gap with a thickness of up to 5 &mgr;m, preferably up to 3 &mgr;m, is provided between the fiber end and the first resonator mirror (26), said air gap being adjustable and controllable and its thickness determining the wavelength of the light emission. 5. Fiber laser according to one of claims1-4, characterized in that the second resonator mirror (28) is highly reflecting for at least one further wavelength range to which the first resonator mirror (26) ist essentially transparent such that laser light is generated in this further wavelength range. 6. Fiber laser according to claim 5, characterized in that the second resonator mirror (28) is tilted relative to the optical axis such that light is simultaneously or separately generated in at least two wavelength ranges. 7. Fiber laser according to one of claims1-6, characterized in that a diaphragm (34) and/or a color filter for controlling the wavelength range of the laser light to be generated is arranged upstream of the second resonator mirror (28). 8. Fiber laser according to claim 7, characterized in that the diaphragm and/or a color filter (34) are controllable such that laser light is simultaneuosly or separately generated in at least two wavelength ranges. 9. Fiber laser according to one of claims4-8, characterized in that the air gap is controllable such that laser light is simultaneously or separately generated in at least two wavelength ranges. 10. Fiber laser according to one of claims5-9, characterized in that the ratio of the light power in the at least two wavelength ranges is adjustable. 11. Fiber laser according to one of claims1-10, characterized in that the resonator unit (26,28) comprises at least one further resonator mirror arranged in the beam path behind the second resonator mirror (28). 12. Fiber laser according to claim 11, characterized in that the at least one further resonator mirror reflects a wavelength range to which the resonator mirror or the resonator mirrors arranged in the beam path upstream of the first resonator mirror are essentially transparent. 13. Fiber laser according to claim 11 or12, characterized in that a diaphragm and/or a color filter for controlling the wavelength range of the laser light to be generated is associated with each further resonator mirror. 14. Fiber laser according to one of claims1-13, characterized in that the resonator unit comprises a shiftable collimating lens (30) for adjusting the wavelength range fed back into the fiber. 15. Fiber laser according to claim 13 or14, characterized in that the collimating lens (30) is configured such that it serves for controlling the emission spectrum. 16. Fiber laser according to one of claims1-15, characterized in that at the entrance end (14) of the fiber (16) a coupling-in mirror (18) transparent to the wavelength range of the pump light is provided. 17. Fiber laser according to claim 16, characterized in that the coupling-in mirror (18) is highly reflecting for the at least one emission wavelength range of the fiber. 18. Fiber laser according to one of claims1-17, characterized in that an optical decoupling means (40) is provided between the pump light source (10) and the entrance end (14) of the fiber (16). 19. Fiber laser according to claim 18, characterized in that the optical decoupling unit (40) comprises a polarizing means. 20. Fiber laser according to claim 19, characterized in that the polarizing means comprises a polarizing filter (44) arranged downstream of the pump light source, the polarizing filter (44) being transparent to the pump light emitted by the pump light source (10), and a polarization-changing means (48) arranged downstream of the polarizing filter (44) such that pump light emerging from the entrance end (14) of the fiber (16) or pump light reflected near the entrance end (14) is polarized such that cannot pass through the polarization filter (44). 21. Fiber laser according to claim 17, characterized in that a Faraday rotator or a λ/4 plate is provided as the polarization-changing means (48). 22. Fiber laser according to one of claims1-21, characterized in that the fiber ends (14,20) are enclosed by a material with similar hardness and have been polished jointly with said material. 23. Fiber laser according to one of claims1-22, characterized in that the enclosing material is a plastic material polymerizing when exposed to UV-radiation. 24. Fiber laser according to one of claims1-20, characterized in that the fiber ends (14,20) are produced by cutting. 25. Fiber laser according to one of claims1-24, characterized in that the first resonator mirror (26) and/or the coupling-in mirror (18) are glued to the exit end (20) and the entrance end (14), respectively. 26. Fiber laser according to claim 25, characterized in that glueing is effected with a low-viscosity adhesive. 27. Fiber laser according to claim 25 or26, characterized in that a two-component epoxy resin adhesive is used as adhesive. 28. Fiber laser according to one of claims1-24, characterized in that the fiber end faces are prepared as mirrors by direct coating. 29. Fiber laser according to one of claims1-28, characterized in that the mirrors (18,26,28) are multilayered dielectric mirrors. 30. Fiber laser according to claim 29, characterized in that the layers comprise two different and alternately arranged materials. 31. Fiber laser according to claim 29, characterized in that one layer comprises hafnium oxide and the other layer comprises silicon oxide. 32. Fiber laser according to one of claims27-31, characterized in that the first resonator mirror (26) comprises two multilayer subsystems reflecting the laser light and/or the pump light. 33. Fiber laser according to one of claims1-32, characterized in that the fiber (16) comprises silicon oxide or ZBLAN glass. 34. Fibre laser according to one of claims1-32, characterized in that the fiber (16) is doped with at least one rare earth, preferably praseodym and/or ytterbium and/or erbium ions. 35. Fiber laser according to claim 34, characterized in that the fiber (16) is doped with 500-5,000 pppm, preferably 2,000-3,000 ppm, praseodym ions. 36. Fiber laser according to claim 34, characterized in that the fiber (16) is doped with 5,000-50,000 ppm, preferably 10,000-30,000 ppm, Ytterbium ions. 37. Fiber laser according to one of claims1-36, characterized in that the cutoff wavelength for higher waveguide modes of the fiber (16) is by 5%-15% larger than the shortest laser emission wavelength. 38. Fiber laser according to one of claims1-37, characterized in that the fiber (16) has a length of 10-60 cm, preferably 20-40 cm. 39. Fiber laser according to one of claims1-38, characterized in that from the intensity of the emission power a control signal is generated which controls the emission power of the fiber laser by energizing the pump light source (10). 40. Fiber laser according to claim 33, characterized in that different control signals are generated from the intensities of the light power simultaneously emitted at different wavelengths. 41. Fiber laser according to claim 39, characterized in that the intensities of the simultaneously emitted light power are determined by coupling out light at the corresponding wavelength with the aid of a split lens. 42. Fiber laser according to claim 39, characterized in that the control signal for the pump light contains a portion proportional to the negative of the time deflection of the laser output power such that rapid natural oscillations of the laser light are dampened. 43. Fiber laser according to claim 39, characterized in that the control signal for the pump light contains portions proportional to the deviation of the laser power from a nominal value and/or to the time integral of said deviation. 44. Fiber laser according to one of claims1-43, characterized in that the gap (d) between fiber end face (14,20) and glued-on mirror (18,26) is filled with a medium having an index of refraction near that of the fiber. 45. Fiber laser according to one of claims1-44, characterized in that the fiber (16) comprises a high numerical aperture, in particular between 0.25 and 0.50. 46. Fiber laser according to one of claims1-45, characterized in that the second resonator mirror (28) is exchangeable for the purpose of tuning the fiber laser. 47. Use of the fiber laser according to one of claims1-46 as a light source for a confocal microscope, in particular for a fluorescent microscope.
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