Apparatus and method for analyte measurement with improved coupling of excitation radiation into material including said analyte

1 . An apparatus for analyzing a material comprising at least one analyte, said apparatus comprising:

a measurement body having a contact surface suitable to be brought in thermal contact or pressure-transmitting contact with the material, said thermal or pressure-transmitting contact permitting heat or pressure waves generated by absorption of excitation radiation in the material to be transferred to said measurement body,

an excitation radiation source configured for irradiating excitation radiation into the material to be absorbed therein, and

a detection device for detecting a physical response of said measurement body, or of a component included therein, to heat or a pressure wave received from the material upon absorption of said excitation radiation and for generating a response signal based on said detected physical response, said response signal being indicative of the degree of absorption of excitation radiation, wherein said measurement body is transparent for said excitation radiation,

wherein said excitation radiation source is configured for providing said excitation radiation as an excitation beam,

wherein said excitation radiation source is arranged such that said excitation beam is irradiated into said measurement body at an entrance surface thereof, propagates through a portion of said measurement body and exits from said measurement body at the contact surface,

wherein said excitation beam impinges on the entrance surface at an angle of 89.0° or less and of 82.0° or more, and

wherein the entrance surface and the contact surface at the respective portions thereof where said excitation beam enters and leaves said measurement body, respectively, are inclined with respect to each other with an angle of 1.0° or more and 8.0° or less.

2 . The apparatus of claim 1 , wherein said excitation beam impinges on the contact surface of said measurement body at an angle of 90°±1.5°.

3 . The apparatus of claim 1 , wherein said detection device comprises a light source for generating a detection light beam travelling through at least a portion of said measurement body or a component included in said measurement body,

said physical response of said measurement body to heat or pressure waves received from the material upon absorption of said excitation radiation is a local change in the refractive index of said measurement body or said component, and

said detection device is configured for detecting one of a change in the light path or a change in the phase of detection beam due to said change in refractive index.

4 . The apparatus of claim 3 , wherein said detection device is configured such that the detection light beam is irradiated into said measurement body at the entrance surface, wherein the detection light beam impinges on the entrance surface at an angle of incidence with respect to the entrance surface of 89° or less and of 80° or more.

5 . The apparatus of claim 4 , wherein said measurement body is received in a frame or receptacle that is configured to turn said measurement body to adjust said angle of incidence of the detection light beam when impinging on the entrance surface of said measurement body, wherein said frame or receptacle is configured to turning said measurement body around an axis parallel with the excitation light beam, or deviating from parallel by less than 10°.

6 . The apparatus of claim 3 , wherein said measurement body is transparent for the detection light beam, the detection light beam is directed to be totally or partially reflected at a surface of said measurement body that is in thermal or pressure-transmitting contact with the material, and wherein said detection device comprises a detector for detecting a degree of deflection of the detection light beam after its reflection at the contact surface, due to said local change in refractive index.

7 . The apparatus of claim 6 , wherein the detection light source is arranged such that the detection light beam is irradiated into said measurement body at the entrance surface, propagates through a portion of said measurement body and exits from said measurement body at an exit surface, wherein a focusing lens is formed integrally with the entrance surface for focusing the detection light beam entering into said measurement body in at least one dimension or a collimating lens is formed integrally with the exit surface for collimating the detection light beam in at least one dimension, or both.

8 . The apparatus of claim 7 , wherein at least one of said focusing lens and said collimating lens is a cylinder lens focusing and collimating the detection light beam at least predominantly in one dimension, respectively.

9 . The apparatus of claim 1 , wherein said detection device comprises an interferometric device configured to assess said change in phase of the detection beam and generate a response signal indicative of said change in phase.

10 . The apparatus of claim 1 , wherein said measurement body or a component in said measurement body has electrical properties that change in response to a local change in temperature or a change in pressure associated therewith, and wherein said detection device comprises electrodes for capturing electrical signals representing said electrical properties.

11 . The apparatus of claim 1 , wherein said apparatus comprises an optical fiber embedded in said measurement body, a detection light source provided at one end of said fiber for coupling detection light into said optical fiber and a mode detector provided at the other end of said fiber, said mode detector being suitable for detecting changes in optical modes of said detection light in response to the heat or pressure waves received by said measurement body from the material.

12 . The apparatus of claim 1 , wherein the material is human skin and said analyte is glucose present in the skin.

13 . The apparatus of claim 1 , wherein said excitation radiation is generated using an array of quantum cascade lasers, each having a dedicated wavelength.

14 . The apparatus of claim 1 , wherein said excitation radiation is generated using at least one tunable quantum cascade laser.

15 . The apparatus of claim 1 , wherein some or all of said excitation radiation has wavelengths in a range of 5 μm to 13 μm.

16 . An apparatus for analyzing a material comprising at least one analyte, said apparatus comprising:

a measurement body having a contact surface suitable to be brought in thermal contact or pressure-transmitting contact with the material, said thermal or pressure-transmitting contact permitting heat or pressure waves generated by absorption of excitation radiation in the material to be transferred to said measurement body,

an excitation radiation source configured for irradiating excitation radiation into the material to be absorbed therein, and

a detection device for detecting a physical response of said measurement body, or of a component included therein, to heat or a pressure wave received from the material upon absorption of said excitation radiation and for generating a response signal based on said detected physical response, said response signal being indicative of the degree of absorption of excitation radiation, wherein said measurement body is transparent for said excitation radiation,

wherein said excitation radiation source is configured for providing said excitation radiation as an excitation beam,

wherein said excitation radiation source is arranged such that said excitation beam is irradiated into said measurement body at an entrance surface thereof, propagates through a portion of said measurement body and exits from said measurement body at the contact surface,

wherein said excitation beam impinges on the entrance surface at an angle of 89.0° or less and of 82.0° or more,

wherein said detection device comprises a light source for generating a detection light beam travelling through at least a portion of said measurement body or a component included in said measurement body, said physical response of said measurement body to heat or pressure waves received from the material upon absorption of said excitation radiation is a local change in the refractive index of said measurement body or said component, and said detection device is configured for detecting one of a change in the light path or a change in the phase of detection beam due to said change in refractive index,

wherein said measurement body is transparent for the detection light beam, the detection light beam is directed to be totally or partially reflected at a surface of said measurement body that is in thermal or pressure-transmitting contact with the material,

wherein said detection device comprises a detector for detecting a degree of deflection of the detection light beam after its reflection at the contact surface, due to said local change in refractive index,

wherein the detection light source is arranged such that the detection light beam is irradiated into said measurement body at the entrance surface, propagates through a portion of said measurement body and exits from said measurement body at an exit surface,

wherein the detection light beam impinges—in absence of any deflection due to said local change in refractive index—on the exit surface at an angle of 5° or more with respect to the normal to the exit surface, such that the detection beam is refracted upon exiting from the exit surface of said measurement body, and

wherein the orientation of the exit surface with respect to the detection light beam is such that said deflection of the detection light beam in response to said heat or pressure waves being transferred to said measurement body increases said angle between the detection light beam and the normal to the exit surface.

17 . An apparatus for analyzing a material comprising at least one analyte, said apparatus comprising:

a measurement body having a contact surface suitable to be brought in thermal contact or pressure-transmitting contact with the material, said thermal or pressure-transmitting contact permitting heat or pressure waves generated by absorption of excitation radiation in the material to be transferred to said measurement body,

an excitation radiation source configured for irradiating excitation radiation into the material to be absorbed therein, and

a detection device for detecting a physical response of said measurement body, or of a component included therein, to heat or a pressure wave received from the material upon absorption of said excitation radiation and for generating a response signal based on said detected physical response, said response signal being indicative of the degree of absorption of excitation radiation, wherein said measurement body is transparent for said excitation radiation,

wherein said excitation radiation source is configured for providing said excitation radiation as an excitation beam,

wherein said excitation radiation source is arranged such that said excitation beam is irradiated into said measurement body at an entrance surface thereof, propagates through a portion of said measurement body and exits from said measurement body at the contact surface,

wherein said excitation beam impinges on the entrance surface at an angle of 89.0° or less and of 82.0° or more,

wherein said detection device comprises a light source for generating a detection light beam travelling through at least a portion of said measurement body or a component included in said measurement body, said physical response of said measurement body to heat or pressure waves received from the material upon absorption of said excitation radiation is a local change in the refractive index of said measurement body or said component, and said detection device is configured for detecting one of a change in the light path or a change in the phase of detection beam due to said change in refractive index,

wherein said measurement body is transparent for the detection light beam, the detection light beam is directed to be totally or partially reflected at a surface of said measurement body that is in thermal or pressure-transmitting contact with the material,

wherein said detection device comprises a detector for detecting a degree of deflection of the detection light beam after its reflection at the contact surface, due to said local change in refractive index,

wherein said detector comprises a position sensitive detector on which the detection light beam impinges, wherein said position sensitive detector is sensitive for detecting shifts in position of the detection light beam impinging thereon in at least one sensing direction,

wherein said position sensitive detector is arranged such that said deflection of the detection light beam leads to a shift of the position of the detection light beam impinging thereon in said at least one sensing direction, and

wherein a cylinder lens is provided in the light path of the detection light beam for shaping the profile of the detection light beam or the position sensitive detector is arranged at an angle with respect to the detection light beam deviating from 90°, such that the diameter of the detection light beam impinging on said position sensitive detector in said sensing direction is at least 1.5 times as large as the diameter of the detection light beam in a direction orthogonal to said sensing direction.

18 . The apparatus of claim 17 , wherein said cylinder lens is a collimating lens arranged in said light path of the detection light beam between its reflection at the contact surface and said position sensitive detector, wherein said cylinder lens is arranged to collimate the detection light beam at least predominantly in a dimension orthogonal to said sensing direction of said position sensitive detector.

19 . An apparatus for analyzing a material comprising at least one analyte, said apparatus comprising:

a measurement body having a contact surface suitable to be brought in thermal contact or pressure-transmitting contact with the material, said thermal or pressure-transmitting contact permitting heat or pressure waves generated by absorption of excitation radiation in the material to be transferred to said measurement body,

an excitation radiation source configured for irradiating excitation radiation into the material to be absorbed therein,

a detection device for detecting a physical response of said measurement body, or of a component included therein, to heat or a pressure wave received from the material upon absorption of said excitation radiation and for generating a response signal based on said detected physical response, said response signal being indicative of the degree of absorption of excitation radiation, wherein said measurement body is transparent for said excitation radiation, and

a beam splitter for splitting a source light beam into a detection light beam and a reference light beam,

wherein said excitation radiation source is configured for providing said excitation radiation as an excitation beam,

wherein said excitation radiation source is arranged such that said excitation beam is irradiated into said measurement body at an entrance surface thereof, propagates through a portion of said measurement body and exits from said measurement body at the contact surface,

wherein said excitation beam impinges on the entrance surface at an angle of 89.0° or less and of 82.0° or more,

wherein said detection device comprises a light source for generating the detection light beam travelling through at least a portion of said measurement body or a component included in said measurement body, said physical response of said measurement body to heat or pressure waves received from the material upon absorption of said excitation radiation is a local change in the refractive index of said measurement body or said component, and said detection device is configured for detecting one of a change in the light path or a change in the phase of detection beam due to said change in refractive index,

wherein said measurement body is transparent for the detection light beam, the detection light beam is directed to be totally or partially reflected at a surface of said measurement body that is in thermal or pressure-transmitting contact with the material,

wherein said detection device comprises a detector for detecting a degree of deflection of the detection light beam after its reflection at the contact surface, due to said local change in refractive index,

wherein said reference light beam is directed to be totally or partially reflected at a surface of said measurement body that is in thermal or pressure-transmitting contact with the material, but in a region where any effect of heat or pressure waves received from the material upon absorption of excitation radiation is negligible, and

wherein said detection device comprises an additional detection device for detecting a degree of deflection of the reference light beam after its reflection at the contact surface.

20 . A method of analyzing a material comprising at least one analyte, said method comprising:

bringing a measurement body having a contact surface in thermal contact or pressure-transmitting contact with the material, said thermal or pressure-transmitting contact permitting heat or pressure waves generated by absorption of excitation radiation in the material to be transferred to said measurement body,

irradiating excitation radiation into the material to be absorbed therein, and

detecting a physical response of said measurement body, or of a component included therein, to heat or a pressure wave received from the material upon absorption of said excitation radiation and generating a response signal based on said detected physical response, said response signal being indicative of the degree of absorption of excitation radiation, wherein said measurement body is transparent for said excitation radiation,

wherein an excitation radiation source provides said excitation radiation as an excitation beam,

wherein said excitation beam is irradiated into said measurement body at an entrance surface thereof, propagates through a portion of said measurement body and exits from said measurement body at the contact surface,

wherein said excitation beam impinges on the entrance surface at an angle of 89.0° or less and of 82.0° or more, and

wherein the entrance surface and the contact surface at the respective portions thereof where said excitation beam enters and leaves said measurement body, respectively, are inclined with respect to each other with an angle of 1.0° or more and 8.0° or less.

21 . The method of claim 20 , wherein said excitation beam impinges on the contact surface of said measurement body at an angle of 90°±1.5°.

22 . The method of claim 20 , wherein said detection comprises generating a detection light beam travelling through at least a portion of said measurement body or a component included in said measurement body, said physical response of said measurement body to heat or pressure waves received from the material upon absorption of said excitation radiation is a local change in the refractive index of said measurement body or said component, and wherein said detecting comprises detecting one of a change in the light path or a change in the phase of detection beam due to said change in refractive index.

23 . The method of claim 22 , wherein the detection light beam is irradiated into said measurement body at the entrance surface such that the detection light beam impinges on the entrance surface at an angle of incidence with respect to the entrance surface of 89° or less and of 80° or more.

24 . The apparatus of claim 23 , wherein said measurement body is received in a frame or receptacle that is configured to turn said measurement body to adjust said angle of incidence of the detection light beam when impinging on the entrance surface of said measurement body, said frame or receptacle is configured to turning said measurement body around an axis parallel with the excitation light beam, or deviating from parallel by less than 10°.

25 . The method of claim 22 , wherein said measurement body is transparent for the detection light beam, the detection light beam is directed to be totally or partially reflected at a surface of said measurement body that is in thermal or pressure-transmitting contact with the material, and wherein said detection comprises detecting a degree of deflection of the detection light beam after its reflection at the contact surface, due to said local change in refractive index.

26 . The method of claim 20 , wherein the detection light beam is irradiated into said measurement body at the entrance surface, propagates through a portion of said measurement body and exits from said measurement body at an exit surface, wherein a focusing lens is formed integrally with the entrance surface for focusing the detection light beam entering into said measurement body in at least one dimension or a collimating lens is formed integrally with the exit surface for collimating the detection light beam in at least one dimension.

27 . The method of claim 20 , wherein said detection comprises using an interferometric device configured to assessing said change in phase of the detection beam and generate a response signal indicative of said change in phase.

28 . The method of claim 20 , wherein said measurement body or a component in said measurement body has electrical properties that change in response to a local change in temperature or a change in pressure associated therewith, and wherein said detection device comprises electrodes for capturing electrical signals representing said electrical properties.

29 . The method of claim 20 , wherein an optical fiber is embedded in said measurement body, a detection light source is provided at one end of said fiber for coupling detection light into said optical fiber and a mode detector is provided at the other end of said fiber, wherein using said mode detector, changes in optical modes of said detection light in response to the heat or pressure waves received by said measurement body from the material are detected.

30 . The method of claim 20 , wherein the material is human skin, and said analyte is glucose present in the interstitial fluid of the skin.

31 . The method of claim 20 , further comprising a step of generating said excitation radiation using an array of quantum cascade lasers, each having a dedicated wavelength.

32 . The method of one of claim 20 , further comprising a step of generating said excitation radiation using at least one tunable quantum cascade laser.

33 . The method of claim 20 , wherein some or all of said excitation radiation has wavelengths in a range of 5 μm to 13 μm.

34 . A method of analyzing a material comprising at least one analyte, said method comprising:

bringing a measurement body having a contact surface in thermal contact or pressure-transmitting contact with the material, said thermal or pressure-transmitting contact permitting heat or pressure waves generated by absorption of excitation radiation in the material to be transferred to said measurement body,

irradiating excitation radiation into the material to be absorbed therein, and

detecting a physical response of said measurement body, or of a component included therein, to heat or a pressure wave received from the material upon absorption of said excitation radiation and generating a response signal based on said detected physical response, said response signal being indicative of the degree of absorption of excitation radiation, wherein said measurement body is transparent for said excitation radiation,

wherein an excitation radiation source provides said excitation radiation as an excitation beam,

wherein said excitation beam is irradiated into said measurement body at an entrance surface thereof, propagates through a portion of said measurement body and exits from said measurement body at the contact surface,

wherein said excitation beam impinges on the entrance surface at an angle of 89.0° or less and of 82.0° or more,

wherein said detection comprises generating a detection light beam travelling through at least a portion of said measurement body or a component included in said measurement body, said physical response of said measurement body to heat or pressure waves received from the material upon absorption of said excitation radiation is a local change in the refractive index of said measurement body or said component,

wherein said detecting comprises detecting one of a change in the light path or a change in the phase of detection beam due to said change in refractive index,

wherein said measurement body is transparent for the detection light beam, the detection light beam is directed to be totally or partially reflected at a surface of said measurement body that is in thermal or pressure-transmitting contact with the material, and wherein said detection comprises detecting a degree of deflection of the detection light beam after its reflection at the contact surface, due to said local change in refractive index,

wherein the detection light source is arranged such that the detection light beam is irradiated into said measurement body at the entrance surface, propagates through a portion of said measurement body and exits from said measurement body at an exit surface,

wherein the detection light beam impinges—in absence of any deflection due to said local change in refractive index—on the exit surface at an angle of 5° or more with respect to the normal to the exit surface, such that the detection beam is refracted upon exiting from the exit surface of said measurement body, and

wherein the orientation of the exit surface with respect to the detection light beam is such that said deflection of the detection light beam in response to said heat or pressure waves being transferred to said measurement body increases said angle between the detection light beam and the normal to the exit surface.

35 . The method of claim 26 , wherein at least one of said focusing lens and said collimating lens is a cylinder lens focusing and collimating the detection light beam at least predominantly in one dimension, respectively.

36 . A method of analyzing a material comprising at least one analyte, said method comprising:

bringing a measurement body having a contact surface in thermal contact or pressure-transmitting contact with the material, said thermal or pressure-transmitting contact permitting heat or pressure waves generated by absorption of excitation radiation in the material to be transferred to said measurement body,

irradiating excitation radiation into the material to be absorbed therein, and

detecting a physical response of said measurement body, or of a component included therein, to heat or a pressure wave received from the material upon absorption of said excitation radiation and generating a response signal based on said detected physical response, said response signal being indicative of the degree of absorption of excitation radiation, wherein said measurement body is transparent for said excitation radiation,

wherein an excitation radiation source provides said excitation radiation as an excitation beam,

wherein said excitation beam is irradiated into said measurement body at an entrance surface thereof, propagates through a portion of said measurement body and exits from said measurement body at the contact surface,

wherein said excitation beam impinges on the entrance surface at an angle of 89.0° or less and of 82.0° or more,

wherein said detection comprises generating a detection light beam travelling through at least a portion of said measurement body or a component included in said measurement body, said physical response of said measurement body to heat or pressure waves received from the material upon absorption of said excitation radiation is a local change in the refractive index of said measurement body or said component,

wherein said detecting comprises detecting one of a change in the light path or a change in the phase of detection beam due to said change in refractive index,

wherein said measurement body is transparent for the detection light beam, the detection light beam is directed to be totally or partially reflected at a surface of said measurement body that is in thermal or pressure-transmitting contact with the material,

wherein said detection comprises detecting a degree of deflection of the detection light beam after its reflection at the contact surface, due to said local change in refractive index,

wherein said detector comprises a position sensitive detector on which the detection light beam impinges, wherein said position sensitive detector detects shifts in position of the detection light beam impinging thereon in at least one sensing direction,

wherein said position sensitive detector is arranged such that said deflection of the detection light beam leads to a shift of the position of the detection light beam impinging thereon in said at least one sensing direction, and

wherein a cylinder lens is provided in the light path of the detection light beam for shaping the profile of the detection light beam or the position sensitive detector is arranged at an angle deviating from 90° from the detection light beam, such that the diameter of the detection light beam impinging on said position sensitive detector in said sensing direction is at least 1.5 times as large as the diameter of the detection light beam in a direction orthogonal to said sensing direction.

37 . The method of claim 36 , wherein said cylinder lens is a collimating lens arranged in said light path of the detection light beam between its reflection at the contact surface and said position sensitive detector, wherein said cylinder lens collimates the detection light beam at least predominantly in a dimension orthogonal to said sensing direction of said position sensitive detector.

38 . A method of analyzing a material comprising at least one analyte, said method comprising:

bringing a measurement body having a contact surface in thermal contact or pressure-transmitting contact with the material, said thermal or pressure-transmitting contact permitting heat or pressure waves generated by absorption of excitation radiation in the material to be transferred to said measurement body,

irradiating excitation radiation into the material to be absorbed therein, and

detecting a physical response of said measurement body, or of a component included therein, to heat or a pressure wave received from the material upon absorption of said excitation radiation and generating a response signal based on said detected physical response, said response signal being indicative of the degree of absorption of excitation radiation, wherein said measurement body is transparent for said excitation radiation,

wherein an excitation radiation source provides said excitation radiation as an excitation beam,

wherein said excitation beam is irradiated into said measurement body at an entrance surface thereof, propagates through a portion of said measurement body and exits from said measurement body at the contact surface,

wherein said excitation beam impinges on the entrance surface at an angle of 89.0° or less and of 82.0° or more,

wherein said detection comprises generating a detection light beam travelling through at least a portion of said measurement body or a component included in said measurement body, said physical response of said measurement body to heat or pressure waves received from the material upon absorption of said excitation radiation is a local change in the refractive index of said measurement body or said component,

wherein said detecting comprises detecting one of a change in the light path or a change in the phase of detection beam due to said change in refractive index,

wherein said measurement body is transparent for the detection light beam, the detection light beam is directed to be totally or partially reflected at a surface of said measurement body that is in thermal or pressure-transmitting contact with the material, and wherein said detection comprises detecting a degree of deflection of the detection light beam after its reflection at the contact surface, due to said local change in refractive index, and

wherein a source light beam is splitted into the detection light beam and a reference light beam, wherein said reference light beam is likewise directed to be totally or partially reflected at a surface of said measurement body that is in thermal or pressure-transmitting contact with the material, but in a region where any effect of heat or pressure waves received from the material upon absorption of excitation radiation is negligible, and wherein a degree of deflection, in particular a deflection angle, of the reference light beam after its reflection at the contact surface is detected.