Optical arrangement for the production of a light-sheet

Abstract

The invention is directed to an optical arrangement with a light source for emitting a light bundle and with optical elements for transforming this light bundle into the shape of a light sheet, particularly suitable for illuminating individual planes of a three-dimensional specimen in selective plane illumination microscopy (SPIM). According to the invention, means are provided for varying the cross section of the light sheet, for varying the length of the light sheet and/or for influencing the direction in which individual beam components extending within the light sheet are directed to the specimen substance. This makes it possible to adapt the geometry of the light sheet to the illumination requirements for observing one and the same specimen plane with a plurality of different objectives and, if required, to reduce shadows occurring within the observed specimen plane as a result of the illumination.

The invention claimed is: 
     
       1. An optical arrangement for generating a light sheet, particularly for illuminating a three-dimensional specimen in selective plane illumination microscopy (SPIM), comprising:
 a light source for emitting a light bundle;   optical elements for transforming said light bundle into the shape of a light sheet;   means for varying the cross section;   means for varying the length; and/or   means for influencing the direction in which beam components extending within the light sheet are directed to the specimen substance;   wherein the aspherical optical element is in the form of a Powell lens; and   wherein the light source emits a light bundle of coherent light, in whose path are provided:
 a collimator; 
 an aspherical optical element; and 
 a lens or lens group for realizing a field diaphragm plane; and 
 a lens or lens group for realizing an aperture diaphragm plane. 
   
     
     
       2. An optical arrangement for generating a light sheet, particularly for illuminating a three-dimensional specimen in selective plane illumination microscopy (SPIM), comprising:
 a light source for emitting a light bundle;   optical elements for transforming said light bundle into the shape of a light sheet;   means for varying the cross section;   means for varying the length; and/or   means for influencing the direction in which beam components extending within the light sheet are directed to the specimen substance;   wherein a plurality of field diaphragms which can be exchanged with one another in the field diaphragm plane and which have different diaphragm openings are provided as means for varying the cross section of the light sheet; and   wherein the light source emits a light bundle of coherent light, in whose path are provided:
 a collimator; 
 an aspherical optical element; and 
 a lens or lens group for realizing a field diaphragm plane; and 
 a lens or lens group for realizing an aperture diaphragm plane. 
   
     
     
       3. An optical arrangement for generating a light sheet, particularly for illuminating a three-dimensional specimen in selective plane illumination microscopy (SPIM), comprising:
 a light source for emitting a light bundle;   optical elements for transforming said light bundle into the shape of a light sheet;   means for varying the cross section;   means for varying the length; and/or   means for influencing the direction in which beam components extending within the light sheet are directed to the specimen substance;   wherein a plurality of aperture diaphragms which can be exchanged with one another in the aperture diaphragm plane and which have different diaphragm openings are provided as means for varying the length of the light sheet; and   wherein the light source emits a light bundle of coherent light in whose path are provided:
 a collimator; 
 an aspherical optical element; and 
 a lens or lens group for realizing a field diaphragm plane; and 
 a lens or lens group for realizing an aperture diaphragm plane. 
   
     
     
       4. An optical arrangement for generating a light sheet, particularly for illuminating a three-dimensional specimen in selective plane illumination microscopy (SPIM), comprising:
 a light source for emitting a light bundle;   optical elements for transforming said light bundle into the shape of a light sheet;   means for varying the cross section;   means for varying the length; and/or   means for influencing the direction in which beam components extending within the light sheet are directed to the specimen substance;   wherein a wobble plate is provided for influencing the direction of beam components; and   wherein the light source emits a light bundle of coherent light, in whose path are provided:
 a collimator; 
 an aspherical optical element; and 
 a lens or lens group for realizing a field diaphragm plane; and 
 a lens or lens group for realizing an aperture diaphragm plane. 
   
     
     
       5. An optical arrangement for generating a light sheet, particularly for illuminating a three-dimensional specimen in selective plane illumination microscopy (SPIM), comprising:
 a light source for emitting a light bundle;   optical elements for transforming said light bundle into the shape of a light sheet;   means for varying the cross section;   means for varying the length; and/or   means for influencing the direction in which beam components extending within the light sheet are directed to the specimen substance;   wherein an oscillating mirror or a polygon scanner is provided for influencing the direction of beam components; and   wherein the light source emits a light bundle of coherent light, in whose path are provided:
 a collimator; 
 an aspherical optical element; and 
 a lens or lens group for realizing a field diaphragm plane; and 
 a lens or lens group for realizing an aperture diaphragm plane. 
   
     
     
       6. An optical arrangement for generating a light sheet, particularly for illuminating a three-dimensional specimen in selective plane illumination microscopy (SPIM), comprising:
 a light source for emitting a light bundle;   optical elements for transforming said light bundle into the shape of a light sheet;   means for varying the cross section;   means for varying the length; and/or   means for influencing the direction in which beam components extending within the light sheet are directed to the specimen substance;   wherein the light source emits a light bundle of spatially partially coherent light, and a cylindrical honeycomb condenser, preferably comprising two one-dimensional cylindrical-lens arrays and collimating optics, is arranged in the path of this light bundle, wherein the lateral coherence length is less than the period of the cylindrical-lens arrays.   
     
     
       7. The optical arrangement according to  claim 6 ;
 wherein a temporally partially coherent light source, particularly in the form of a broadband laser, is provided for generating the spatially partially coherent light, a dispersive optical element.   
     
     
       8. The optical arrangement according to  claim 7 ;
 wherein the dispersive optical element is in the form of a grating and the coherent light source is in the form of a broadband laser.   
     
     
       9. An optical arrangement for generating light sheet, particularly for illuminating a three-dimensional specimen in selective plane illumination microscopy (SPIM), comprising:
 a light source for emitting a light bundle;   optical elements for transforming said light bundle into the shape of a light sheet;   means for varying the cross section;   means for varying the length; and/or   means for influencing the direction in which beam components extending within the light sheet are directed to the specimen substance;   wherein the light source comprises an array of individual laser light sources, and a cylindrical lens or a GRIN lens is arranged downstream of this array.   
     
     
       10. An optical arrangement for generating a light sheet, particularly for illuminating a three-dimensional specimen in selective plane illumination microscopy (SPIM), comprising:
 a light source for emitting a light bundle;   optical elements for transforming said light bundle into the shape of a light sheet;   means for varying the cross section;   means for varying the length; and/or   means for influencing the direction in which beam components extending within the light sheet are directed to the specimen substance;   wherein a micro-optical element is provided for transforming the light bundle into the shape of a light sheet and has a homogenizing effect in one cross-sectional axis and, at the same time, a focusing effect in the orthogonal cross-sectional axis.   
     
     
       11. The optical arrangement according to  claim 10 ;
 wherein the micro-optical element has optically active free-form surfaces or in the form of a GRIN lens.   
     
     
       12. An optical arrangement for generating a light sheet, particularly for illuminating a three-dimensional specimen in selective plane illumination microscopy (SPIM), comprising:
 a light source for emitting a light bundle;   optical elements for transforming said light bundle into the shape of a light sheet;   means for varying the cross section;   means for varying the length; and/or   means for influencing the direction in which beam components extending within the light sheet are directed to the specimen substance;   wherein the light source emits a light bundle of coherent light, within whose path are provided:
 anamorphotic optics for generating a light bundle with an elliptic cross section; 
 an optical deflection device downstream of the latter for generating a scanning movement of this light bundle; and 
 a focusing lens or lens group through which the scanned light bundle is directed to the specimen. 
   
     
     
       13. The optical arrangement according to  claim 12 ;
 wherein the anamorphotic optics is in the form of a cylindrical-lens telescope and the optical deflection device is preferably in the form of an oscillating mirror.   
     
     
       14. An optical arrangement for generating a light sheet for illuminating a three-dimensional specimen in selective plane illumination microscopy (SPIM), comprising:
 means for forming a light sheet from light; and   light sheet influencing means for influencing the direction in which beam components extending within the light sheet are directed to the specimen substance such that the beam components strike the specimen substance successively in time in alternating directions such that shadows caused by non-transparent specimen substances within the illuminated plane are at least substantially reduced or prevented.   
     
     
       15. The optical arrangement according to claim 14 wherein the light sheet influencing means comprises:
 an optical deflection device,   wherein the optical deflection device is positioned such that when the light sheet strikes the optical deflection device, oscillating movements of the optical deflection device influence the direction of beam components to strike the specimen substance successively in time in alternating directions.   
     
     
       16. The optical arrangement according to claim 15 wherein the optical deflection device comprises:
 a wobble plate.   
     
     
       17. The optical arrangement according to claim 16, comprising:
 the wobble plate being located in a pupil plane of the illumination beam path of the light sheet and positioned such that when the light sheet strikes the wobble plate, the oscillating movements of the wobble plate influence the direction of beam components to strike the specimen substance successively in time in alternating directions and at alternating angles.   
     
     
       18. The optical arrangement according to claim 15 wherein the optical deflection device comprises:
 an oscillating mirror or polygon scanner.   
     
     
       19. The optical arrangement according to claim 18 comprising:
 the oscillating mirror or polygon scanner being positioned in a plane conjugate to a field diaphragm plane.   
     
     
       20. The optical arrangement according to claim 14 comprising:
 a light source for emitting a light bundle; and   wherein the means for forming a light sheet from light comprise optical elements for transforming the light bundle into the shape of the light sheet.   
     
     
       21. A method for generating a light sheet for illuminating a three-dimensional specimen in selective plane illumination microscopy (SPIM), comprising:
 forming a light sheet from light; and   deflecting the light sheet to influence the direction in which beam components extending within the light sheet are directed to the specimen substance such that the beam components strike the specimen substance successively in time in alternating directions such that shadows caused by non-transparent specimen substances within the illuminated plane are at least substantially reduced or prevented.   
     
     
       22. The method according to claim 21 wherein method comprises:
 deflecting the light sheet using an optical deflection device positioned in an optical arrangement such that when the light sheet strikes the optical deflection device, oscillating movements of the optical deflection device influence the direction of beam components to strike the specimen substance successively in time in alternating directions.   
     
     
       23. The method according to claim 22 wherein the method comprises:
 deflecting the light sheet using a wobble plate positioned in a pupil plane of the illumination beam path of the light sheet,   wherein the wobble plate is positioned such that that when the light sheet strikes the wobble plate, the oscillating movements of the wobble plate influence the direction of beam components to strike the specimen substance successively in time in alternating directions and at alternating angles.   
     
     
       24. The method according to claim 22 wherein the method comprises:
 deflecting the light sheet using an oscillating mirror or polygon scanner, the oscillating mirror or polygon scanner being positioned in a plane conjugate to a field diaphragm plane.   
     
     
       25. The method according to claim 21 wherein the method comprises:
 emitting a light bundle from a light source; and   wherein the forming the light sheet from light comprises transforming the light bundle into the shape of the light sheet with optical elements.   
     
     
       26. An optical arrangement for generating a light sheet, particularly for illuminating a three-dimensional specimen in selective plane illumination microscopy (SPIM), comprising:
 a light source for emitting a light bundle;   optical elements for transforming said light bundle into the shape of a light sheet;   means for varying the cross section;   means for varying the length; and/or   means for influencing the direction in which beam components extending within the light sheet are directed to the specimen substance;   wherein the aspherical optical element is in the form of a Powell lens; and   wherein the light source emits a light bundle of coherent light, in whose path are provided:
 a collimator; 
 an aspherical optical element; and 
 a lens or lens group for realizing a field diaphragm plane; and 
 a lens or lens group for realizing an aperture diaphragm plane. 
   
     
     
       27. An optical arrangement for generating a light sheet, particularly for illuminating a three-dimensional specimen in selective plane illumination microscopy (SPIM), comprising:
 a light source for emitting a light bundle;   optical elements for transforming said light bundle into the shape of a light sheet;   means for varying the cross section;   means for varying the length; and/or   means for influencing the direction in which beam components extending within the light sheet are directed to the specimen substance;   wherein a plurality of field diaphragms which can be exchanged with one another in the field diaphragm plane and which have different diaphragm openings are provided as means for varying the cross section of the light sheet; and   wherein the light source emits a light bundle of coherent light, in whose path are provided:
 a collimator; 
 an aspherical optical element; and 
 a lens or lens group for realizing a field diaphragm plane; and 
 a lens or lens group for realizing an aperture diaphragm plane. 
   
     
     
       28. An optical arrangement for generating a light sheet, particularly for illuminating a three-dimensional specimen in selective plane illumination microscopy (SPIM), comprising:
 a light source for emitting a light bundle;   optical elements for transforming said light bundle into the shape of a light sheet;   means for varying the cross section;   means for varying the length; and/or   means for influencing the direction in which beam components extending within the light sheet are directed to the specimen substance;   wherein a plurality of aperture diaphragms which can be exchanged with one another in the aperture diaphragm plane and which have different diaphragm openings are provided as means for varying the length of the light sheet; and   wherein the light source emits a light bundle of coherent light in whose path are provided:
 a collimator; 
 an aspherical optical element; and 
 a lens or lens group for realizing a field diaphragm plane; and 
 a lens or lens group for realizing an aperture diaphragm plane. 
   
     
     
       29. An optical arrangement for generating a light sheet, particularly for illuminating a three-dimensional specimen in selective plane illumination microscopy (SPIM), comprising:
 a light source for emitting a light bundle;   optical elements for transforming said light bundle into the shape of a light sheet;   means for varying the cross section;   means for varying the length; and/or   means for influencing the direction in which beam components extending within the light sheet are directed to the specimen substance;   wherein a wobble plate is provided for influencing the direction of beam components; and   wherein the light source emits a light bundle of coherent light, in whose path are provided:
 a collimator; 
 an aspherical optical element; and 
 a lens or lens group for realizing a field diaphragm plane; and 
 a lens or lens group for realizing an aperture diaphragm plane. 
   
     
     
       30. An optical arrangement for generating a light sheet, particularly for illuminating a three-dimensional specimen in selective plane illumination microscopy (SPIM), comprising:
 a light source for emitting a light bundle;   optical elements for transforming said light bundle into the shape of a light sheet;   means for varying the cross section; means for varying the length; and/or   means for influencing the direction in which beam components extending within the light sheet are directed to the specimen substance;   wherein an oscillating mirror or a polygon scanner is provided for influencing the direction of beam components; and   wherein the light source emits a light bundle of coherent light, in whose path are provided:
 a collimator; 
 an aspherical optical element; and 
 a lens or lens group for realizing a field diaphragm plane; and 
 a lens or lens group for realizing an aperture diaphragm plane. 
   
     
     
       31. An optical arrangement for generating a light sheet, particularly for illuminating a three-dimensional specimen in selective plane illumination microscopy (SPIM), comprising:
 a light source for emitting a light bundle;   optical elements for transforming said light bundle into the shape of a light sheet;   means for varying the cross section; means for varying the length; and/or   means for influencing the direction in which beam components extending within the light sheet are directed to the specimen substance;   wherein the light source emits a light bundle of spatially partially coherent light, and a cylindrical honeycomb condenser, preferably comprising two one-dimensional cylindrical-lens arrays and collimating optics, is arranged in the path of this light bundle, wherein the lateral coherence length is less than the period of the cylindrical-lens arrays.   
     
     
       32. The optical arrangement according to claim 31;
 wherein a temporally partially coherent light source, particularly in the form of a broadband laser, is provided for generating the spatially partially coherent light, a dispersive optical element.   
     
     
       33. The optical arrangement according to claim 32;
 wherein the dispersive optical element is in the form of a grating and the coherent light source is in the form of a broadband laser.   
     
     
       34. An optical arrangement for generating light sheet, particularly for illuminating a three-dimensional specimen in selective plane illumination microscopy (SPIM), comprising:
 a light source for emitting a light bundle;   optical elements for transforming said light bundle into the shape of a light sheet;   means for varying the cross section;   means for varying the length; and/or   means for influencing the direction in which beam components extending within the light sheet are directed to the specimen substance;   wherein the light source comprises an array of individual laser light sources, and a cylindrical lens or a GRIN lens is arranged downstream of this array.   
     
     
       35. An optical arrangement for generating a light sheet, particularly for illuminating a three-dimensional specimen in selective plane illumination microscopy (SPIM), comprising:
 a light source for emitting a light bundle;   optical elements for transforming said light bundle into the shape of a light sheet;   means for varying the cross section; means for varying the length; and/or   means for influencing the direction in which beam components extending within the light sheet are directed to the specimen substance;   wherein a micro-optical element is provided for transforming the light bundle into the shape of a light sheet and has a homogenizing effect in one cross-sectional axis and, at the same time, a focusing effect in the orthogonal cross-sectional axis.   
     
     
       36. The optical arrangement according to claim 35;
 wherein the micro-optical element has optically active free-form surfaces or in the form of a GRIN lens.   
     
     
       37. An optical arrangement for generating a light sheet, particularly for illuminating a three-dimensional specimen in selective plane illumination microscopy (SPIM), comprising:
 a light source for emitting a light bundle;   optical elements for transforming said light bundle into the shape of a light sheet;   means for varying the cross section;   means for varying the length; and/or   means for influencing the direction in which beam components extending within the light sheet are directed to the specimen substance;   wherein the light source emits a light bundle of coherent light, within whose path are provided:
 anamorphotic optics for generating a light bundle with an elliptic cross section; 
 an optical deflection device downstream of the latter for generating a scanning movement of this light bundle; and 
 a focusing lens or lens group through which the scanned light bundle is directed to the specimen. 
   
     
     
       38. The optical arrangement according to claim 37;
 wherein the anamorphotic optics is in the form of a cylindrical-lens telescope and the optical deflection device is preferably in the form of an oscillating mirror.