Abstract:
Low coherence interferometer apparatus for investigation of a sample (15), in particular for multidimensional imaging, having an interferometer configuration (2) comprising a low coherence light source, a probe head (9) having a light exit opening (16) for irradiating light into the sample, an optical coupler, a reference reflector and a detector (13). The optical paths between the elements of the interferometer configuration (2) form interferometer arms. The optical coupler and the reference arm of the interferometer configuration (2) are integrated into a common optical chip (28). In addition to the reference reflector (11), the reference arm comprises a deflection reflector (33) formed on an end surface (35) of the optical chip (28) in such a manner that the reference light is cross-coupled between a first light guide (10a) forming a first portion of the reference arm (10) and a second light guide (10b) forming a second portion of the reference arm (10).
Abstract:
Method for determining an analyte in a scattering matrix. In a detection step detection measurements are made in which light is irradiated into the matrix as primary light and light leaving the scattering matrix is detected as secondary light, in order to determine as a measurement quantity a measurable physical property of the light which is variable due to the interaction of the light with the matrix. Information on the presence of the analyte in the matrix is determined in an evaluation step. The determination of optically weakly absorbing analytes against a strongly absorbing interference background is improved by the use of two selection methods for the depth selective detection of the secondary light in combination with one another. Primary light is focused by means of a primary light optically focussing element onto a region of focus lying in the matrix at a predetermined measuring depth and the region of focus is imaged by means of a secondary light optically focusing element onto a light entry aperture arranged in the light path of the secondary light to the detector. In addition to this first depth selection by a confocal arrangement, a second depth selection device is used to detect light reflected from a defined measuring depth as secondary light, with the measuring depth coinciding with the depth of focus.
Abstract:
A method for the analytical determination of the glucose concentration in a biological sample. In a detection step, light is irradiated into the sample and the light emerging therefrom after interaction with the sample emerges therefrom is detected in order to measure a physical light property affected by said interaction. The glucose concentration is determined from this measurement in an evaluation step. To provide a method for determining glucose in reagent-free and non-invasive manner, the invention proposes that a portion of the light emitted by the light source be guided along a reference light path of defined optical path length to the photodetector, that the total measuring light path also has a defined optical length and that the measuring light path after it has traversed the sample is so combined with the reference light path that the measuring light and the reference light interfere with each other. The photodetector measures an interference signal used in the evaluation step to determine the glucose concentration.
Abstract:
Low coherence interferometer apparatus for investigation of a sample (15), in particular for multi-dimensional imaging, having an interferometer configuration (2) comprising a low coherence light source, a probe head (9) having a light exit opening (16) for irradiating light into the sample, an optical coupler, a reference reflector and a detector (13). The optical paths between the elements of the interferometer configuration (2) form interferometer arms. The optical coupler and the reference arm of the interferometer configuration (2) are integrated into a common optical chip (28). In addition to the reference reflector (11), the reference arm comprises a deflection reflector (33) formed on an end surface (35) of the optical chip (28) in such a manner that the reference light is cross-coupled between a first light guide (10a) forming a first portion of the reference arm (10) and a second light guide (10b) forming a second portion of the reference arm (10).
Abstract:
The invention concerns a method for investigating a scattering medium, especially a biological matrix, with intensity-modulated light. In order, in such a frequency-domain measuring procedure, to reduce the expenditure on electronics without restricting accuracy of measurement, a method is proposed, in which, in order to investigate a scattering medium, especially a biological matrix, with intensity-modulated light, a high-frequency modulation signal is generated by a frequency generator (18), the intensity of a light emitter (10) is modulated with a modulation signal and the light from the light emitter (10) is radiated into the medium, the modulation signal includes frequency chirps during which the modulation frequency is tuned from an initial frequency to a final frequency, the modulation signal is delivered from the frequency generator (18) via at least two different signal paths (23A, 24) to a signal mixer (31), so that during a frequency chirp the input signals of the signal mixer (31) differ by a differential frequency whose magnitude is a function of the difference between the signal transit times over the at least two signal paths (23A, 24) and of the rate of change of the modulation frequency, wherein at least one of the signal paths includes a light path section (20A) passing through the medium as a measurement signal path (23A), and the output signal of the signal mixer (31) is further processed to produce information relating to the scattering medium (FIG. 2).