Broadband Light Source Having a Microstructured Optical Fiber for Endoscopic and Fluorescence Microscopic Examination Devices, in Particular for Special Devices for Optical Biopsy

Abstract

The invention relates to an arrangement for generating a broadband spectrum that can be used in particular as a light source for short coherence interferometry and confocal microscopy as well as endoscopic short coherence interferometry and endoscopic confocal microscopy. The arrangement comprises a laser, in particular a laser diode, for generating a short light pulse of wavelength λ P and a microstructured optical fiber ( 1 ) of high nonlinearity, that has a null dispersion of the group velocity in the vicinity of the wavelength λ P and an anomalous dispersion, as well as means for coupling the light pulse into the microstructured optical fiber.

1 . A light source ( 8 ) which has a broadband spectrum, comprising
 a laser ( 2 ) for generating a short light pulse of wavelength λ P ,   a microstructured optical fiber ( 1 ) which has a null dispersion of the group velocity in the vicinity of the wavelength λ P  and an anomalous dispersion, and   means ( 3 ) for coupling the light pulse into the microstructured optical fiber ( 1 ),   wherein the microstructured optical fiber ( 1 ) has a refractive index n which is dependent on radiant intensity and where n(I)=n 0 +n 2 *I at the wavelength λ P , where n 2 ≧2*10 −20  cm 2 /W.   
     
     
         2 . (canceled) 
     
     
         3 . The light source ( 8 ) as claimed in  claim 1 , wherein the microstructured optical fiber ( 1 ) comprises a nonlinear optical material. 
     
     
         4 . The light source ( 8 ) as claimed in  claim 1 , wherein the microstructured optical fiber ( 1 ) comprises at least one material formed from at least one of a multicomponent glass, a multicomponent glass-ceramic, a monocrystalline material, a polycrystalline material, a plastic matrix composite and a liquid-crystal material. 
     
     
         5 . The light source ( 8 ) as claimed in  claim 4 , wherein the optical material has at least one of isotropic and anisotropic properties. 
     
     
         6 . The light source ( 8 ) as claimed in  claim 4 , wherein the microstructured optical fiber ( 1 ) comprises at least one nonoxidic multicomponent glass. 
     
     
         7 . The light source ( 8 ) as claimed in  claim 6 , wherein the nonoxidic multicomponent glass is a chalcogenide glass that includes at least As and Sn. 
     
     
         8 . The light source ( 8 ) as claimed in  claim 4 , wherein the microstructured optical fiber ( 1 ) comprises at least one oxidic multicomponent glass. 
     
     
         9 . The light source ( 8 ) as claimed in  claim 8 , wherein the oxidic multicomponent glass comprises a silicate glass which has at least one element selected from the group consisting of alkali metals (Li 2 O, Na 2 O, K 2 O, Rb 2 O, Cs 2 O) or at least one element selected from the group consisting of alkaline-earth metals (MgO, CaO, SrO, BaO), or at least one element selected from each group thereof. 
     
     
         10 . The light source ( 8 ) as claimed in  claim 9 , wherein the oxidic multicomponent glass has at least one further element selected from the group consisting of Al 2 O 3 , B 2 O 3 , PbO, ZnO, TiO 2 , ThO 2 , ZrO 2 , La 2 O 3 , CeO 2  and P 2 O 5 . 
     
     
         11 . The light source ( 8 ) as claimed in  claim 10 , wherein the oxidic multicomponent glass comprises a heavy flint glass which has the components SiO 2  and PbO and at least one of the components Al 2 O 3 , B 2 O 3 , TiO 2 , ThO 2 , La 2 O 3 , BaO, Li 2 O, Na 2 O and K 2 O. 
     
     
         12 . (canceled) 
     
     
         13 . The light source ( 8 ) as claimed in  claim 4 , wherein the microstructured optical fiber ( 1 ) comprises at least one oxidic multicomponent glass-ceramic. 
     
     
         14 . The light source ( 8 ) as claimed in  claim 13 , wherein the multicomponent glass ceramic has at least one crystal phase formed from at least one of the following: strontium niobate, potassium hydrogen phosphate (KTP), BBO, LBO, LiIO 3 , LiNbO 3 , KnbO 3 , AgGaS 3 , AgGaSe 2 , PPLN and BaTiO 3 . 
     
     
         15 . The light source ( 8 ) as claimed in  claim 4 , wherein the microstructured optical fiber ( 1 ), comprises at least one monocrystalline material formed from one of the following: strontium niobate, potassium hydrogen phosphate (KTP), BBO, LBO, LiIO 3 , LiNbO 3 , KnbO 3 , AgGaS 3 , AgGaSe 2 , PPLN and BaTiO 3 . 
     
     
         16 . The light source ( 8 ) as claimed in  claim 4 , wherein the microstructured optical fiber ( 1 ) comprises at least one polycrystalline material formed from at least one of the following: strontium niobate, potassium hydrogen phosphate (KTP), BBO, LBO, LiIO 3 , LiNbO 3 , KnbO 3 , AgGaS 3 , AgGaSe 2 , PPLN and BaTiO 3 . 
     
     
         17 . The light source ( 8 ) as claimed in  claim 4 , wherein the microstructured optical fiber ( 1 ) comprises a plastic-matrix composite formed from an oxidic multicomponent glass, and plastics based on one of the following: PMMA (polymethylmethacrylate), PC (polycarbonate), PA (polyamide) and PE (polyethylene). 
     
     
         18 . The light source ( 8 ) as claimed in  claim 4 , wherein the microstructured optical fiber ( 1 ) comprises a liquid crystal which has at least one polymeric fraction with a mesogenic group within one of (i) the main polymer chain and (ii) a side chain branching off therefrom. 
     
     
         19 . The light source ( 8 ) as claimed in  claim 1 , wherein the microstructured optical fiber ( 1 ) has a fiber core ( 1 . 1 ) running along the fiber length, and a structured fiber cladding arranged around the fiber core ( 1 . 1 ). 
     
     
         20 . The light source ( 8 ) as claimed in  claim 19 , wherein the fiber core ( 1 . 1 ) comprises a solid body, and the fiber cladding comprises hollow structures running parallel to the fiber core ( 1 . 1 ). 
     
     
         21 . The light source ( 8 ) as claimed in  claim 20 , wherein the fiber core ( 1 . 1 ) comprises a solid rod, and the fiber cladding comprises tubes ( 1 . 2 ) arranged uniformly around the solid rod. 
     
     
         22 . The light source ( 8 ) as claimed in  claim 21 , wherein the fiber core ( 1 . 1 ) has a diameter of from 1 μm to 4 μm, and the tubes ( 1 . 2 ) have a diameter of from 2 μm to 8 μm. 
     
     
         23 . The light source ( 8 ) as claimed in  claim 19 , wherein the microstructured optical fiber ( 1 ) can be produced using an IR drawing process in accordance with the US Application 03SGL0308USP. 
     
     
         24 . The light source ( 8 ) as claimed in  claim 1 , wherein the laser ( 2 ) comprises a laser diode ( 2 ) for generating a short light pulse. 
     
     
         25 . The light source ( 8 ) as claimed in  claim 24 , wherein the light pulses of the laser diode ( 2 ) have a pulse duration of from 1 picosecond to 10 nanoseconds. 
     
     
         26 . The light source ( 8 ) as claimed in  claim 24 , wherein the light pulses of the laser diode ( 2 ) have a wavelength λ P  in the region from 500 nm≦λ P ≦1800 nm. 
     
     
         27 . The light source ( 8 ) as claimed in  claim 23 , wherein the broadband spectrum comprises a wavelength from 400 nm to 2000 nm. 
     
     
         28 . The light source ( 8 ) as claimed in  claim 1 , wherein the means ( 3 ) for coupling the light pulse into the microstructured optical fiber ( 1 ) comprise a free-beam optical system comprising a positioning unit ( 4 ,  5 ) and an imaging optical system for beam focusing. 
     
     
         29 . The light source ( 8 ) as claimed in  claim 1 , wherein the means ( 3 ) for coupling the light pulse into the microstructured optical fiber ( 1 ) comprise a coupling optical waveguide and a plug connection. 
     
     
         30 . The light source ( 8 ) as claimed in  claim 29 , wherein the plug connection has a guide which orientates the coupling optical waveguide and the microstructured optical fiber ( 1 ) parallel to one another. 
     
     
         31 . The light source ( 8 ) as claimed in  claim 30 , wherein the plug connection has a ferrule. 
     
     
         32 . The light source ( 8 ) as claimed in  claim 1 , wherein the means ( 3 ) for coupling the light pulse into the microstructured optical fiber ( 1 ) comprise a coupling optical waveguide and a splice connection. 
     
     
         33 . The light source ( 8 ) as claimed in  claim 1 , defined by its use as a light source ( 8 ) for short coherence interferometry. 
     
     
         34 . The light source ( 8 ) as claimed in  claim 33 , defined by its use as a light source ( 8 ) for OCT. 
     
     
         35 . The light source ( 8 ) as claimed in  claim 1 , defined by its use in imaging endoscopy. 
     
     
         36 . The light source ( 8 ) as claimed in  claim 1 , defined by its use as a light source ( 8 ) for a confocal microscope. 
     
     
         37 . The light source ( 8 ) as claimed in  claim 1 , defined by its use as a light source ( 8 ) for a fluorescence microscope. 
     
     
         38 . The light source ( 8 ) as claimed in  claim 1 , wherein the light source defines a short-coherence measuring appliance. 
     
     
         39 . An endoscope defined by a light source ( 8 ) which has a broadband spectrum, comprising
 a laser ( 2 ) for generating a short light pulse of wavelength λ P ,   a microstructured optical fiber ( 1 ) which has a null dispersion of the group velocity in the vicinity of the wavelength λ P  and an anomalous dispersion, and   means ( 3 ) for coupling the light pulse into the microstructured optical fiber ( 1 ),   wherein the microstructured optical fiber ( 1 ) has a refractive index n which is dependent on radiant intensity and where n(I)=n 0 +n 2 *I at the wavelength λ P , wherein n 2 ≧2*10 −20  cm 2 /W.   
     
     
         40 . The endoscope as claimed in  claim 39  having a short coherence tomography device, wherein the short coherence tomography device is itself defined by the light source ( 8 ). 
     
     
         41 . The endoscope as claimed in  claim 40 , in which the short coherence tomography device is arranged in the endoscope and is provided with at least one of an imaging device, a light-guiding fiber and an electronic detector. 
     
     
         42 . A confocal microscope defined by a light source ( 8 ) which has a broadband spectrum, comprising
 a laser ( 2 ) for generating a short light pulse of wavelength λ P ,   a microstructured optical fiber ( 1 ) which has a null dispersion of the group velocity in the vicinity of the wavelength λ P  and an anomalous dispersion, and   means ( 3 ) for coupling the light pulse into the microstructured optical fiber ( 1 ),   wherein the microstructured optical fiber ( 1 ) has a refractive index n which is dependent on radiant intensity and where n(I)=n 0 +n 2 *I at the wavelength λ P , where n 2 ≧2*10 −20  cm 2 /W.   
     
     
         43 . The confocal microscope as claimed in  claim 42 , wherein said confocal microscope is part of an endoscope. 
     
     
         44 . The confocal microscope as claimed in  claim 42 , defined by a wavelength region of the light source ( 8 ) from approximately 350 nm to 790 nm. 
     
     
         45 . A fluorescence microscope defined by a light source ( 8 ) which has a broadband spectrum, comprising
 a laser ( 2 ) for generating a short light pulse of wavelength λ P ,   a microstructured optical fiber ( 1 ) which has a null dispersion of the group velocity in the vicinity of the wavelength λ P  and an anomalous dispersion, and   means ( 3 ) for coupling the light pulse into the microstructured optical fiber ( 1 ),   wherein the microstructured optical fiber ( 1 ) has a refractive index n which is dependent on radiant intensity and where n(I)=n 0 +n 2 *I at the wavelength λ P , where n 2 ≧2*10 −20  cm 2 /W.   
     
     
         46 . The fluorescence microscope as claimed in  claim 45 , defined by a wavelength region of the light source ( 8 ) from approximately 250 nm to 1200 nm.