Grid-waveguide structure for reinforcing an excitation field and use thereof

• US 20030108291A1
• Filed: 10/08/2002
• Published: 06/12/2003
• Est. Priority Date: 04/14/2000
• Status: Abandoned Application

• Current Assignee: Bayer Technology Services GmbH (Bayer AG)
• Original Assignee: Bayer Technology Services GmbH (Bayer AG)
• Inventors: Pawlak, Michael, Bopp, Martin Andreas, Duveneck, Gert Ludwig, Ehrat, Markus
• Application Number:
  US10/257,036
• Publication Number:
  US 20030108291A1
• Time in Patent Office: Days
• US Class Current: 385/37
• CPC Class Codes: G01N 2021/6419 Excitation at two or more wavelengths
• CPC Class Codes: G01N 2021/7786 Fluorescence
• CPC Class Codes: G01N 21/6428 Measuring fluorescence of fluorescent products of reactions or of fluorochrome labelled reactive substances, e.g. measuring quenching effects, using measuring "optrodes" in vivo A61B5/00; immunoassay G01N33/53
• CPC Class Codes: G01N 21/648 using evanescent coupling or surface plasmon coupling for the excitation of fluorescence
• CPC Class Codes: G01N 21/774 the reagent being on a grating or periodic structure
• CPC Class Codes: G02B 6/124 Geodesic lenses or integrated gratings

Abstract

The invention relates to a variable embodiment of a grating waveguide structure, based on a planar thin-film waveguide with a first optically transparent layer (a) on a second optically transparent layer (b) having a lower refractive index than layer (a), and a grating structure (c) modulated in layer (a), wherein the intensity of an excitation light irradiated at the resonance angle for incoupling into layer (a) is enhanced by at least a factor of 100 on layer (a) and within layer (a), at least in the region of the grating structure (c), in comparison with the intensity of said excitation light on a substrate surface without incoupling of the excitation light. The invention also relates to an optical system with an excitation light source and an embodiment of a grating waveguide structure according to the invention, and to a method for enhancing an excitation light intensity, and to the use thereof in bioanalytical detection processes, in non-linear optics or in telecommunications or communications industry.

Claims

1. Grating waveguide structure, comprising a planar thin-film waveguide, with a layer (a), transparent at least at one excitation wavelength, on a second layer (b) with lower refractive index than layer (a), also transparent at least at said excitation wavelength, and at least one grating structure (c) modulated in layer (a), wherein the intensity of an excitation light irradiated at the resonance angle for incoupling into layer (a) is enhanced by at least a factor of 100 on layer (a) and within layer (a), at least in the region of the grating structure (c), in comparison with the intensity of said excitation light on a substrate surface without incoupling of the excitation light.

2. Grating waveguide structure according to claim 1, wherein the intensity of an excitation light irradiated at the resonance angle for incoupling into layer (a) is enhanced by at least a factor of 1000 on layer (a) and within layer (a), at least in the region of the grating structure (c), in comparison with the intensity of said excitation light on a substrate surface without incoupling of the excitation light.

3. Grating waveguide structure according to claim 1, wherein the intensity of an excitation light irradiated at the resonance angle for incoupling into layer (a) is enhanced by at least a factor of 10000 on layer (a) and within layer (a), at least in the region of the grating structure (c), in comparison with the intensity of said excitation light on a substrate surface without incoupling of the excitation light.

4. Grating waveguide structure according to claim 1, wherein the intensity of an excitation light irradiated at the resonance angle for incoupling into layer (a) is enhanced by at least a factor of 100000 on layer (a) and within layer (a), at least in the region of the grating structure (c), in comparison with the intensity of said excitation light on a substrate surface without incoupling of the excitation light.

5. Grating waveguide structure according to any of claims 1-4, wherein the excitation light intensity on layer (a) is sufficiently large to excite luminescence from a molecule located on the surface of layer (a) or at a distance below 200.nm from layer (a) by two-photon absorption.

6. Grating waveguide structure according to claim 5, wherein the excitation light intensity on layer (a) is sufficiently large simultaneously on an area of at least 1 mm² on said grating waveguide structure to excite luminescence from molecules located on the surface of layer (a) or at a distance below 200.nm from layer (a) by two-photon absorption.

7. Grating waveguide structure according to any of claims 1-6, wherein the grating waveguide structure comprises means for a signal transfer to an adjacent grating waveguide structure.

8. Grating waveguide structure according to claim 7, wherein a luminescence generated on or in the near-field of layer (a) by two-photon absorption is transmitted to an adjacent grating waveguide structure upon outcoupling by a grating structure (c).

9. Grating waveguide structure according to any of claims 1-8, wherein said structure comprises continuous, unmodulated regions of layer (a), which are preferably arranged in direction of propagation of an excitation light incoupled by a grating structure (c) and guided in layer (a).

10. Grating waveguide structure according to any of claims 1-9, wherein said structure comprises a multitude of grating structures (c) with identical or different period, optionally adjacent thereto with continuous, unmodulated regions of layer (a) on a common, continuous substrate.

11. Grating waveguide structure according to any of claims 1-10, wherein a luminescence generated on or in the near-field of layer (a) by two-photon absorption, is coupled at least partially into layer (a) and is propagated to adjacent regions of said grating waveguide structure by guiding in layer (a).

12. Grating waveguide structure according to any of claims 1-11, wherein the intensity of the excitation light on layer (a) and within layer (a) is sufficiently high, at least in the region of the grating structure (c), for switching the transmission properties of the grating structure (c) for a light signal guided in layer (a).

13. Grating waveguide structure according to claim 12, characterized in that it allows for switching the transmission properties of the grating structure (c) by means of an excitation light launched from the outside of layer (a) onto said grating structure.

14. Grating waveguide structure according to any of claims 12-13, wherein said grating structure (c) is preferably provided as a “

Bragg grating”

, and the switching function is based on the change of the grating function from transmission to reflection of a light signal guided in layer (a), due to a change of the optical refractive index in the region of the grating structure caused by the amplified excitation light intensity in layer (a).

15. Grating waveguide structure according to any of claims 1-14, characterized in that said structure comprises a superposition of two or more grating structures of different periodicity, with grating lines arranged in parallel or non-parallel, preferably non-parallel, which structure is operable for the incoupling of excitation light of different wavelengths, wherein, in case of two superimposed grating structures their grating lines are preferably arranged perpendicular to each other.

16. Grating waveguide structure according to any of claims 1-15, wherein a further optically transparent layer (b′

) with lower refractive index than the one of layer (a) and with a thickness of 5 nm-10000 nm, preferably of 10 nm-1000 nm, is located between layers (a) and (b) and in contact with layer (a).

17. Grating waveguide structure according to any of claims 1-14 or 16, wherein the grating structure (c) is a diffractive grating with a uniform period or a multidiffractive grating.

18. Grating waveguide structure according to any of claims 1-18, wherein the grating structure (c) is provided with a laterally varying periodicity, perpendicular or in parallel to the direction of propagation of the excitation light coupled into the optically transparent layer (a).

19. Grating waveguide structure according to any of claims 1-18, wherein the material of the second optically transparent layer (b) comprises glass, quartz or a transparent thermoplastic or moldable plastics, for example from the group formed by polycarbonate, polyimide or poly methylmethacrylate.

20. Grating waveguide structure according to any of claims 1-19, wherein the refractive index of the first optically transparent layer (a) is larger than 1.8.

21. Grating waveguide structure according to any of claims 1-20, wherein the first optically transparent layer (a) comprises a material of the group of TiO₂, ZnO, Nb₂O₅, Ta₂O₅, HfO₂, or ZrO₂, especially preferred of TiO₂ or Nb₂O₅ or Ta₂O₅, or of a material with high third-order nonlinearity of the refractive index, such as poly diacetylene, poly toluenesulfonate or poly phenylenevinylene.

22. Grating waveguide structure according to any of claims 1-21, wherein the product of the thickness of layer (a) and of its refractive index is between one tenth and a whole, preferably between one third and two thirds, of the excitation wavelength of the excitation light to be coupled into layer (a).

23. Grating waveguide structure according to any of claims 1-22, wherein grating structures (c) modulated in layer (a) have a period of 200 nm-1000 nm and a modulation depth of 3 nm to 100 nm, preferably of 10 nm-30 nm.

24. Grating waveguide structure according to any of claims 1-23, wherein the ratio of the modulation depth of the grating to the thickness of the first optically transparent layer (a) is equal or smaller than 0.2.

25. Grating waveguide structure according to any of claims 1-24, wherein the grating structure (c) is a relief grating with a rectangular, triangular or semi-circular profile or a phase or volume grating with a periodic modulation of the refractive index in the essentially planar, optically transparent layer (a).

26. Grating waveguide structure according to any of claims 1-25, wherein optically or mechanically recognizable marks for simplifying adjustments in an optical system and/or for the connection to sample compartments as part of an analytical system are provided on said structure.

27. Grating waveguide structure according to any of claims 1-26, wherein an adhesion-promoting layer (f) is deposited on the optically transparent layer (a), for immobilization of biological or biochemical or synthetic recognition elements (e) for the determination of one or more analytes in a supplied sample, with a thickness of preferably less than 200 nm, most preferably of less than 20 nm, and wherein the adhesion-promoting layer (f) preferably comprises a compound from the group comprising silanes, epoxides, functionalized, charged or polar polymers, and “

self-organized functionalized monolayers”

.

28. Grating waveguide structure according to any of claims 1-27, wherein laterally separated measurement areas (d) are generated by laterally selective deposition of biological or biochemical or synthetic recognition elements on said grating waveguide structure, preferably by applying elements one or more methods of the group of methods comprising ink jet spotting, mechanical spotting, micro contact printing, fluidic contacting of the measurement areas with the biological or biochemical or synthetic recognition elements upon their supply in parallel or crossed micro channels, upon application of pressure differences or electric or electromagnetic potentials.

29. Grating waveguide structure according to any of claims 1-28, wherein components of the group formed by nucleic acids (e.g. DNA, RNA, oligonucleotides) and nucleic acid analogues (e.g. PNA), antibodies, aptamers, membrane-bound and isolated receptors, their ligands, antigens for antibodies, “

histidin-tag components”

, cavities generated by chemical synthesis, for hosting molecular imprints. etc., or whole cells or cell fragments are deposited as biological or biochemical or synthetic recognition elements.

30. Grating waveguide structure according to any of claims 1-29, wherein compounds, that are “

chemically neutral”

towards the analyte, are deposited between the laterally separated measurement areas (d), preferably for example out of the groups formed by albumins, especially bovine serum albumin or human serum albumin, fragmented natural or synthetic DNA not hybridizing with polynucleotides to be analyzed, such as herring or salmon sperm, or also uncharged but hydrophilic polymers, such as poly ethyleneglycols or dextranes.

31. Grating waveguide structure according to any of claims 28-30, wherein two or more laterally separated measurement areas are combined to segments on the grating waveguide structure, and that preferably different segments are additionally separated from each other by a deposited rim supporting the fluidic sealing between adjacent areas and/or contributing to a reduction of the optical cross-talk between adjacent areas.

32. Grating waveguide structure according to any of claims 28-31, wherein up to 1000000 measurement areas are provided in a two-dimensional arrangement, and wherein a single measurement area occupies an area of 0.001 mm²-6 mm².

33. Optical system for amplification of the intensity of an excitation light, comprising at least one excitation light source and a grating waveguide structure according to any of claims 1-32, wherein the intensity of an excitation light irradiated at the resonance angle for incoupling into layer (a) is enhanced by at least a factor of 100 on layer (a) and within layer (a), at least in the region of the grating structure (c), in comparison with the intensity of said excitation light on a substrate surface without incoupling of the excitation light.

34. Optical system according to claim 33, wherein the intensity of an excitation light irradiated at the resonance angle for incoupling into layer (a) is enhanced by at least a factor of 1000 on layer (a) and within layer (a), at least in the region of the grating structure (c), in comparison with the intensity of said excitation light on a substrate surface without incoupling of the excitation light.

35. Optical system according to claim 33, wherein the intensity of an excitation light irradiated at the resonance angle for incoupling into layer (a) is enhanced by at least a factor of 10000 on layer (a) and within layer (a), at least in the region of the grating structure (c), in comparison with the intensity of said excitation light on a substrate surface without incoupling of the excitation light.

36. Optical system according to claim 33, wherein the intensity of an excitation light irradiated at the resonance angle for incoupling into layer (a) is enhanced by at least a factor of 100000 on layer (a) and within layer (a), at least in the region of the grating structure (c), in comparison with the intensity of said excitation light on a substrate surface without incoupling of the excitation light.

37. Optical system according to any of claims 33-36, optical system, characterized in that the excitation light intensity on layer (a) is sufficiently large to excite luminescence from a molecule located on the surface of layer (a) or at a distance below 200.nm from layer (a) by two-photon absorption.

38. Optical system according to claim 37, wherein the excitation light intensity on layer (a) is sufficiently large simultaneously on an area of at least 1 mm² on said grating waveguide structure to excite luminescence from molecules located on the surface of layer (a) or at a distance below 200.nm from layer (a) by two-photon absorption.

39. Optical system according to any of claims 33-38, wherein a luminescence generated on or in the near-field of layer (a) by two-photon absorption is transmitted to an adjacent grating waveguide structure upon outcoupling by a grating structure (c).

40. Optical system according to any of claims 33-39, wherein the grating waveguide structure comprises continuous, unmodulated regions of layer (a), which are preferably arranged in direction of propagation of an excitation light incoupled by a grating structure (c) and guided in layer (a).

41. Optical system according to any of claims 33-40, wherein the grating waveguide structure comprises a multitude of grating structures (c) with identical or different period, optionally adjacent thereto with continuous, unmodulated regions of layer (a) on a common, continuous substrate.

42. Optical system according to any of claims 33-41, wherein a luminescence generated on or in the near-field of layer (a) by two-photon absorption, is coupled at least partially into layer (a) and is propagated to adjacent regions of said grating waveguide structure by guiding in layer (a).

43. Optical system according to any of claims 33-42, wherein the intensity of the excitation light on layer (a) and within layer (a) is sufficiently high, at least in the region of the grating structure (c), for switching the transmission properties of the grating structure (c) for a light signal guided in layer (a).

44. Optical system according to claim 43, characterized in that switching the transmission properties of the grating structure (c) is possible by means of an excitation light launched from the outside of layer (a) onto said grating structure.

45. Optical system according to any of claims 33-44, wherein said grating structure (c) is provided as a “

Bragg grating”

, and the switching function is based on the change of the grating function from transmission to reflection of a light signal guided in layer (a), due to a change of the optical refractive index in the region of the grating structure caused by the amplified excitation light intensity in layer (a).

46. Optical system according to any of claims 33-45, wherein said optical system comprises at least one detector for the measurement of one or more luminescences from the grating waveguide structure.

47. Optical system according to any of claims 33-46, wherein the excitation light emitted from the at least one excitation light source is essentially parallel and irradiated on a grating structure modulated in the optically transparent layer (a) at the resonance angle for incoupling into layer (a).

48. Optical system according to any of claims 33-47, wherein the excitation light from at least one light optics is expanded to an essentially parallel ray bundle by an expansion optics and irradiated on a grating structure (c) of macroscopic area modulated in the optically transparent layer (a) at the resonance angle for incoupling into layer (a).

49. Optical system according to any of claims 33-47, wherein the excitation light from the at least one light source is divided into a plurality of individual rays of as uniform as possible intensity by a diffractive optical element, or in case of multiple light sources, by multiple diffractive optical elements, which are preferably Dammann gratings, or by refractive optical elements, which are preferably microlens arrays, the individual rays being launched essentially parallel to each other on grating structures (c) the resonance angle for incoupling into layer (a).

50. Optical system according to any of claims 33-49, wherein two or more light sources of similar or different emission wavelength are used as excitation light sources.

51. Optical system according to claim 50, with a grating waveguide structure according to claim 15, wherein the excitation light from two or more light sources is launched simultaneously or sequentially from different directions on a grating structure (c) and incoupled by that structure into layer (a), said grating structure comprising a superposition of grating structures of different periodicity.

52. Optical system according to any of claims 33-51, wherein at least one laterally resolving detector is used for signal detection, for example from the group formed by CCD cameras, CCD chips, photodiode arrays, avalanche diode arrays, multichannel plates and multichannel photomultipliers.

53. Optical system according to any of claims 33-52, wherein optical components of the group formed by lenses or lens systems for the shaping of the transmitted light bundles, planar or curved mirrors for the deviation and optionally additional shaping of the light bundles, prisms for the deviation and optionally spectral separation of the light bundles, dichroic mirrors for the spectrally selective deviation of parts of the light bundles, neutral density filters for the regulation of the transmitted light intensity, optical filters or monochromators for the spectrally selective transmission of parts of the light bundles, or polarization selective elements for the selection of discrete polarization directions of the excitation and/or luminescence light are located between the one or more excitation light sources and the grating waveguide structure according to the invention and/or between said grating waveguide structure and the one or more detectors.

54. Optical system according to any of claims 33-53, wherein the excitation light is launched in pulses with a duration between 1 fsec and 10 min and the emission light from the measurement areas is measured time-resolved.

55. Optical system according to any of claims 33-54, wherein, for referencing purposes, that light signals of the group formed by excitation light at the location of the light sources or after expansion of the excitation light or after its dividing into individual beams, scattered light at the excitation wavelength from the location of the one or more laterally separated measurement areas, and light of the excitation wavelength outcoupled by the grating structure (c) besides the measurement areas are measured.

56. Optical system according to claim 55, wherein the measurement areas for determination of the emission light and of the reference signal are identical.

57. Optical system according to any of claims 33-56, wherein launching of the excitation light and detection of the emission light from one or more measurement areas is performed sequentially for one or more measurement areas.

58. Optical system according to claim 57, wherein sequential excitation and detection is performed by means of movable optical components of the group formed by mirrors, deviating prisms, and dichroic mirrors.

59. Optical system according to claim 57, wherein sequential excitation and detection is performed using an essentially focus and angle preserving scanner.

60. Optical system according to any of claims 57-59, wherein the grating waveguide structure is moved between steps of sequential excitation and detection.

61. Method for amplification of an excitation light intensity, wherein the intensity of an excitation light irradiated at the resonance angle for incoupling into layer (a) on a grating structure (c) modulated in layer (a) of a grating waveguide structure, according to any of claims 1-32, is enhanced by at least a factor of 100 on layer (a) and within layer (a), at least in the region of the grating structure (c), in comparison with the intensity of said excitation light on a substrate surface without incoupling of the excitation light.

62. Method according to claim 61, wherein the intensity of an excitation light irradiated at the resonance angle for incoupling into layer (a) on a grating structure (c) modulated in layer (a) is enhanced by at least a factor of 1000 on layer (a) and within layer (a), at least in the region of the grating structure (c), in comparison with the intensity of said excitation light on a substrate surface without incoupling of the excitation light.

63. Method according to claim 61, wherein the intensity of an excitation light irradiated at the resonance angle for incoupling into layer (a) on a grating structure (c) modulated in layer (a) is enhanced by at least a factor of 10000 on layer (a) and within layer (a), at least in the region of the grating structure (c), in comparison with the intensity of said excitation light on a substrate surface without incoupling of the excitation light.

64. Method according to claim 61, wherein the intensity of an excitation light irradiated at the resonance angle for incoupling into layer (a) on a grating structure (c) modulated in layer (a) is enhanced by at least a factor of 100000 on layer (a) and within layer (a), at least in the region of the grating structure (c), in comparison with the intensity of said excitation light on a substrate surface without incoupling of the excitation light.

65. Method according to any of claims 61-64, wherein the excitation light intensity on layer (a) is sufficiently large to excite luminescence from a molecule located on the surface of layer (a) or at a distance below 200.nm from layer (a) by two-photon absorption.

66. Method according to claim 65, wherein the excitation light intensity on layer (a) is sufficiently large simultaneously on an area of at least 1 mm² on said grating waveguide structure to excite luminescence from molecules located on the surface of layer (a) or at a distance below 200.nm from layer (a) by two-photon absorption.

67. Method according to any of claims 61-66, wherein a luminescence generated on or in the near-field of layer (a) by two-photon absorption is transmitted to an adjacent grating waveguide structure upon outcoupling by a grating structure (c).

68. Method according to any of claims 61-67, wherein the grating waveguide structure comprises continuous, unmodulated regions of layer (a), which are preferably arranged in direction of propagation of an excitation light incoupled by a grating structure (c) and guided in layer (a).

69. Method according to any of claims 61-68, wherein the grating waveguide structure comprises a multitude of grating structures (c) with identical or different period, optionally adjacent thereto with continuous, unmodulated regions of layer (a) on a common, continuous substrate.

70. Method according to any of claims 61-69, wherein a luminescence generated on or in the near-field of layer (a) by two-photon absorption, is coupled at least partially into layer (a) and is propagated to adjacent regions of said grating waveguide structure by guiding in layer (a).

71. Method according to any of claims 61-70, wherein the intensity of the excitation light on layer (a) and within layer (a) is sufficiently high, at least in the region of the grating structure (c), for switching the transmission properties of the grating structure (c) for a light signal guided in layer (a).

72. Method according to claim 71, characterized in that it allows for switching the transmission properties of the grating structure (c) by means of an excitation light launched from the outside of layer (a) onto said grating structure.

73. Method according to any of claims 71-72, wherein said grating structure (c) is provided as a “

Bragg grating”

, and the switching function is based on the change of the grating function from transmission to reflection of a light signal guided in layer (a), due to a change of the optical refractive index in the region of the grating structure caused by the amplified excitation light intensity in layer (a).

74. Method according to any of claims 71-73, wherein a first excitation light as a signal light, in the form of temporal pulse or continuously, is coupled into layer (a) by a first grating structure and is guided in layer (a), until said incoupled, guided signal light arrives in the region of another grating structure (c′

) structured in layer (a), with the same or a grating period different from the one of said first grating structure (c), an excitation light irradiated from externally, as a switching light in the form of a temoral pulse or continuously, being incoupled into layer (a) by means of said second grating structure, and, due to the associated amplification of this switching light by at least a factor of 100 on layer (a) and within layer (a) at least in the region of the grating structure, in comparison with the intensity of this excitation light on a substrate surface without incoupling of the excitation light, the refractive index of layer (a) is changed at least in the region of grating structure (c′

), due to high third-order nonlinearity, so that the function of said grating structure (c′

) is changed from transmission to reflection of said signal light.

75. Method for the detection of one or more analytes by luminescence detection, in one or more samples on one or more measurement areas of a grating waveguide structure according to any of claims 28-32, for the determination of one or more luminescences from a measurement area or from an array of at least two or more laterally separated measurement areas (d) or of at least two or more laterally separated segments comprising several measurement areas on said grating waveguide structure, wherein the intensity of an excitation light irradiated at the resonance angle for incoupling into layer (a) is enhanced by at least a factor of 100 on layer (a) and within layer (a), at least in the region of the grating structure (c), in comparison with the intensity of said excitation light on a substrate surface without incoupling of the excitation light.

76. Method according to claim 75, wherein the intensity of an excitation light irradiated at the resonance angle for incoupling into layer (a) is enhanced by at least a factor of 1000 on layer (a) and within layer (a), at least in the region of the grating structure (c), in comparison with the intensity of said excitation light on a substrate surface without incoupling of the excitation light.

77. Method according to claim 75, wherein the intensity of an excitation light irradiated at the resonance angle for incoupling into layer (a) is enhanced by at least a factor of 10.000 on layer (a) and within layer (a), at least in the region of the grating structure (c), in comparison with the intensity of said excitation light on a substrate surface without incoupling of the excitation light.

78. Method according to claim 75, wherein the intensity of an excitation light irradiated at the resonance angle for incoupling into layer (a) is enhanced by at least a factor of 100.000 on layer (a) and within layer (a), at least in the region of the grating structure (c), in comparison with the intensity of said excitation light on a substrate surface without incoupling of the excitation light.

79. Method according to any of claims 71-78, wherein the excitation light intensity on layer (a) is sufficiently large to excite luminescence from a molecule located on the surface of layer (a) or at a distance below 200.nm from layer (a) by two-photon absorption.

80. Method according to claim 79, wherein the excitation light intensity on layer (a) is sufficiently large simultaneously on an area of at least 1 mm² on said grating waveguide structure to excite luminescence from molecules located on the surface of layer (a) or at a distance below 200.nm from layer (a) by two-photon absorption.

81. Method according to any of claims 61-80, wherein (1) the isotropically emitted luminescence or (2) the luminescence that is coupled back into the optically transparent layer (a) and outcoupled by grating structures (c) or luminescences of both parts (1) and (2) simultaneously are measured.

82. Method according to any of claims 61-81, wherein, for the generation of luminescence, a luminescence dye or luminescent nanoparticle is used as a luminescence label, which can be excited at a wavelength between 200 nm and 1100 nm.

83. Method according to claim 82, wherein said luminescence label is excited by two-photon absorption.

84. Method according to claim 83, wherein said luminescence label is excited to an ultraviolet or blue luminescence by two-photon absorption of an excitation light in the visible or near infrared.

85. Method according to any of claims 82-84, wherein the luminescence label is bound to the analyte or, in a competitive assay, to an analyte analogue or, in a multi-step assay, to one of the binding partners of the immobilized biological or biochemical or synthetic recognition elements or to the biological or biochemical or synthetic recognition elements.

86. Method according to any of claims 82-85, wherein a second or more luminescence labels of similar or different excitation wavelength as the first luminescence label and similar or different emission wavelength are used.

87. Method according to claim 86, wherein the second or more luminescence labels can be excited at the same wavelength as the first luminescence dye, but emit at other wavelengths.

88. Method according to claim 86, wherein the excitation and emission spectra of the applied luminescent dyes do not or only partially overlap.

89. Method according to claim 86, wherein charge or optical energy transfer from a first luminescent dye acting as a donor to a second luminescent dye acting as an acceptor is used for the detection of the analyte.

90. Method according to any of claims 61-89, wherein the one or more luminescences and/or determinations of light signals at the excitation wavelengths are performed polarization-selective, wherein preferably the one or more luminescences are measured at a polarization that is different from the one of the excitation light.

91. Method according to any of claims 61-90, wherein molecules located on the surface of layer (a) or at distance of less than 200 nm from layer (a) are trapped within this distance, due to the large amplification of an irradiated excitation light on layer (a) and within layer (a), as the high surface-confined excitation light intensity and its increasing gradient in direction towards the surface exposes these molecules to the effect of an “

optical tweezers”

.

92. Method according to any of claims 61-91 for the simultaneous or sequential, quantitative or qualitative determination of one or more analytes of the group comprising antibodies or antigens, receptors or ligands, chelators or “

histidin-tag components”

, oligonucleotides, DNA or RNA strands, DNA or RNA analogues, enzymes, enzyme cofactors or inhibitors, lectins and carbohydrates.

93. Method according to at least one of claims 61-92, wherein the samples to be examined are naturally occurring body fluids, such as blood, serum, plasma, lymph or urine or egg yolk, or optically turbid liquids or surface water or soil or plant extracts or bio- or process broths or are taken from biological tissue pieces.

94. Use of a method according to any of claims 61-93 for the determination of chemical, biochemical or biological analytes in screening methods in pharmaceutical research, combinatorial chemistry, clinical and preclinical development, for real-time binding studies and the determination of kinetic parameters in affinity screening and in research, for qualitative and quantitative analyte determinations, especially for DNA- and RNA analytics, for the generation of toxicity studies and the determination of expression profiles and for the determination of antibodies, antigens, pathogens or bacteria in pharmaceutical product development and research, human and veterinary diagnostics, agrochemical product development and research, for patient stratification in pharmaceutical product development and for the therapeutic drug selection, for the determination of pathogens, nocuous agents and germs, especially of salmonella, prions and bacteria, in food and environmental analytics.

95. Use of a grating waveguide structure according to any of claims 1-32 and/or of an optical system according to any of claims 33-60 and/or of a method according to any of claims 61-93 in nonlinear optics or telecommunication or communication techniques.

96. Use of a grating waveguide structure according to any of claims 1-32 and/or of an optical system according to any of claims 33-60 and/or of a method according to any of claims 61-93 for surface-confined investigations which require the application of very high excitation light intensities and/or excitation durations, such as studies of photostabilities of materials, photocatalytic processes etc.