Device for supporting chromophore elements

Abstract

A device for supporting chromophore elements suitable for emitting fluorescence in response to light excitation, the device comprising a substrate having a surface layer carrying the chromophore elements, forming a planar waveguide, and containing photoluminescent constituents which emit guided luminescence at the excitation wavelength(s) of the chromophore elements when they are excited by primary excitation light illuminating the surface layer. The invention is particularly applicable to biochip type devices.

What is claimed is: 
     
       1. A device for supporting chromophore elements suitable for emitting fluorescence in response to light excitation, the device comprising a substrate having a surface layer carrying the chromophore elements and forming a planar waveguide, wherein the planar waveguide contains photoluminescent constituents suitable for emitting luminescence at the excitation wavelengths of the chromophore elements when said constituents are themselves excited by primary excitation light, the emitted luminescence being guided in the planar waveguide to excite the chromophore elements, and further wherein wavelength filter means are provided in the planar waveguide to eliminate the luminescence emitted by the photoluminescent constituents at wavelengths that are identical or close to the wavelengths of the fluorescence emitted by the chromophore elements. 
     
     
       2. A device according to  claim 1 , wherein the photoluminescent constituents comprise in particular: polymers, organic molecules, luminescent ions, or quantum boxes, or they are formed in a layered semiconductor heterostructure. 
     
     
       3. A device according to  claim 1 , wherein the photoluminescent constituents are excited by the primary excitation light illuminating the planar waveguide or the face of the substrate opposite from its face including the planar waveguide. 
     
     
       4. A device according to  claim 1 , wherein the photoluminescent constituents are disposed in the planar waveguide in separate zones substantially adjacent to the zones for carrying the chromophore elements. 
     
     
       5. A device according to  claim 1 , wherein the filter means are situated in the zones for carrying the chromophore elements. 
     
     
       6. A device according to  claim 1 , wherein the filter means are situated between the zones including the photoluminescent components and the zones for carrying the chromophore elements. 
     
     
       7. A device according to  claim 1 , wherein the filter means are constituted by series of grooves, by photonic crystals, or by optical cavities formed in the planar waveguide. 
     
     
       8. A device according to  claim 7 , wherein the grooves of the filter means have low index contrast or are of shallow sinusoidal shape, and are formed on the surface or in intermediate sublayers of the planar waveguide. 
     
     
       9. A device according to  claim 1 , wherein the filter means comprise materials included in the planar waveguide that are absorbent at wavelengths that are identical or close to those of the fluorescence emitted by the chromophore elements. 
     
     
       10. A device according to  claim 1 , wherein, since the excitation wavelength of the chromophore elements is shorter than the wavelength of the fluorescence emitted by said elements, the filtering is performed by the planar waveguide itself, said waveguide having a cut-off wavelength for its guided mode that lies between the excitation wavelength of the chromophore elements and the wavelength of the fluorescence emitted by said elements. 
     
     
       11. A device according to  claim 1 , wherein the photoluminescent constituents are distributed in substantially uniform manner within the planar waveguide. 
     
     
       12. A device according to  claim 1 , wherein the planar waveguide contains different photoluminescent constituents emitting luminescence at different wavelengths in order to excite chromophore elements of different types. 
     
     
       13. A device according to  claim 12 , wherein the different photoluminescent constituents are mixed together in the planar waveguide. 
     
     
       14. A device according to  claim 12 , wherein the photoluminescent constituents of a given type emitting at a given wavelength are separate from other photoluminescent constituents emitting on different wavelengths. 
     
     
       15. A device according to  claim 14 , wherein the photoluminescent constituents of different types are in different zones of the planar waveguide, or are in different superposed layers of the waveguide. 
     
     
       16. A device according to  claim 1 , wherein, beneath at least a portion of the planar waveguide, the substrate includes a layer of material absorbing the photons emitted from the waveguide at the wavelengths of the primary excitation light and/or of the excitation light for the chromophore elements. 
     
     
       17. A device according to  claim 1 , wherein, beneath a zone of the planar waveguide for carrying chromophore elements, the substrate includes a structured intermediate layer that reflects at least part of the fluorescence emitted by the chromophore elements and that includes zones of different thicknesses or heights enabling the intensity of said fluorescence to to be caused to vary by destructive or constructive interference. 
     
     
       18. A device according to  claim 1 , wherein, in the vicinity of at least one zone containing photoluminescent constituents, the planar waveguide includes reflector-forming means for guiding the emitted luminescence towards at least one zone for carrying chromophore elements. 
     
     
       19. A device according to  claim 18 , wherein the reflector-forming means comprise a reflective coating formed on the edge of the planar waveguide, or grooves formed in the planar waveguide, or two-dimensional photonic crystals formed in the planar waveguide. 
     
     
       20. A device according to  claim 1 , wherein, beneath the planar waveguide containing the photoluminescent constituents, the substrate includes a layer of material that is reflective at the wavelengths of the emitted luminescence. 
     
     
       21. A device according to  claim 1 , wherein the planar waveguide includes resonant cavities formed by reflective layers placed on either side of the photoluminescent constituents. 
     
     
       22. A device according to  claim 21 , wherein the photoluminescent constituents are placed at the level of a vertical resonance node for the emitted light. 
     
     
       23. A device according to  claim 21 , wherein the photoluminescent constituents are excited by the primary excitation light illuminating the planar waveguide or the face of the substrate opposite from its face including the planar waveguide, and the photoluminescent constituents are placed at the level of a vertical resonance antinode for the primary excitation light. 
     
     
       24. A device according to  claim 1 , wherein the photoluminescent constituents are placed under a reflective layer at a level corresponding to a vertical resonance node for the emitted luminescence, and are illuminated by the primary excitation light through the face of the substrate opposite from its face including said reflective layer. 
     
     
       25. A device according to  claim 1 , wherein the photoluminescent constituents are placed in a thin layer on a guiding layer of the substrate. 
     
     
       26. A device according to  claim 1 , wherein the photoluminescent constituents are formed in a multilayer semiconductor structure secured to the substrate and optically coupled to a guiding layer deposited on the substrate for the purpose of carrying the chromophore elements. 
     
     
       27. A device according to  claim 1 , wherein its surface layer is covered in a layer having a thickness of several tens of micrometers, including orifices forming microwells for receiving samples.