A method of analyzing a material (12) comprising at least one analyte, said method comprising a material status analyzing procedure (76), in which a present status of the material is analyzed, wherein based on a result of said material status analyzing procedure (76), at least one of a selection of analyte-characteristic-wavelengths used during an analyte measurement procedure (78), an absolute time or a relative time proportion of use of analyte-characteristic-wavelengths during said analyte measurement procedure (78), an individual excitation radiation intensity, or a relative weight given to the wavelengths in the analysis, a selection of analyte-characteristic-wavelengths to be used simultaneously during said analyte measurement procedure (78), and a selection of one or more main frequencies of the modulation of said excitation radiation (18) intensity to be used during said analyte measurement procedure (78) is determined.

A method of analyzing a material (12) comprising at least one analyte, wherein analyte-wavelength-specific measurements are interspersed with reference measurements (80), and wherein response signals obtained for the reference measurements (80) are used for one or more of calibrating an excitation radiation source (26) for generating said excitation radiation, calibrating said detection device, recognizing a variation in the measurement conditions by comparing results of individual reference measurements (80), adapting the analyte measurement procedure (78) with respect to one or more of the entire duration thereof, the absolute or relative duration of analyte-wavelength-specific measurements for a given analyte-characteristic-wavelength, or terminating and/or restarting the analyte measurement procedure, and adapting the analysis carried out in the analyzing step.

Disclosed herein is an apparatus (10) for analyzing a material (12) comprising at least one analyte, said apparatus (10) comprising a measurement body (16) having a contact surface (14) suitable to be brought in thermal contact or pressure-transmitting contact with said material (12), an excitation radiation source configured for irradiating excitation radiation into the material (12) to be absorbed therein, and a detection light source for generating a detection light beam (22) travelling through at least a portion of said measurement body (16) or a component included in said measurement body, wherein said detection light beam is directed to be totally or partially reflected at said contact surface (14), wherein said contact surface (14) of the measurement body is curved in at least one principal direction in the area where the detection light beam (22) is reflected.

A refractometer includes an enclosure, a single use prism, a light source, and an index of refraction (IoR) sensor. The single use prism is removably disposed within the enclosure. The light source and IoR sensor are disposed within the housing and are configured to be repeatably used with a series of single use prisms of similar construction. One single use prism can be removed after being used, and a new single use prism can be installed in the enclosure for use with the same light source and IoR sensor as were used with the first prism.

An apparatus and a method for in-situ phase determination are provided. The apparatus includes a measurement chamber configured to retain a substance, and an entrance window mounted on a side of the measurement chamber. An exit window is mounted on an opposite side of the measurement chamber, and the exit window is parallel with the entrance window. The apparatus further includes a light source configured to generate an incident light beam. The incident light beam is directed to the entrance window at a non-zero angle of incidence with respect to a normal of the entrance window. The incident light beam passes through the entrance window, the measurement chamber and the exit window to form an output light beam. A detector is positioned under the exit window and configured to collect the output light beam passing through the exit window and generate measurement data.

An apparatus and a method for in-situ phase determination are provided. The apparatus includes a measurement chamber configured to retain a substance, and an entrance window mounted on a side of the measurement chamber. An exit window is mounted on an opposite side of the measurement chamber, and the exit window is parallel with the entrance window. The apparatus further includes a light source configured to generate an incident light beam. The incident light beam is directed to the entrance window at a non-zero angle of incidence with respect to a normal of the entrance window. The incident light beam passes through the entrance window, the measurement chamber and the exit window to form an output light beam. A detector is positioned under the exit window and configured to collect the output light beam passing through the exit window and generate measurement data.

A method for determining the refractive index profile of a preform when the RIP is not substantially symmetrical. (i) The preform is scanned, starting with a first projection angle, and raw data are created representing the object through measured data. (ii) Optionally, the object is rotated and step (i) repeated iteratively until all projection angles have been scanned and all measured data have been created. (iii) The measured data are processed to form a sinogram and, if the optional step (ii) has been completed, the method proceeds to step (v). (iv) The object is rotated and steps (i) and (iii) are repeated iteratively until all projection angles have been scanned. (v) A 2D RIP is calculated. (vi) A line section of interest is selected within the 2D RIP. (vii) A fitting procedure is applied to the line section of interest. (viii) Finally, refractive index steps/gradients and dimensions are determined.

A method for determining the refractive index profile of a preform when the RIP is not substantially symmetrical. (i) The preform is scanned, starting with a first projection angle, and raw data are created representing the object through measured data. (ii) Optionally, the object is rotated and step (i) repeated iteratively until all projection angles have been scanned and all measured data have been created. (iii) The measured data are processed to form a sinogram and, if the optional step (ii) has been completed, the method proceeds to step (v). (iv) The object is rotated and steps (i) and (iii) are repeated iteratively until all projection angles have been scanned. (v) A 2D RIP is calculated. (vi) A line section of interest is selected within the 2D RIP. (vii) A fitting procedure is applied to the line section of interest. (viii) Finally, refractive index steps/gradients and dimensions are determined.