Abstract: According to an example aspect of the present invention, there is provided a method for analysing a chemical composition of a target, the method comprising placing an electrically tunable Fabry-Perot interferometer in a path of radiation emitted by a radiation source, and detecting the radiation, which has passed the Fabry-Perot interferometer and which has passed or was reflected by the target, by means of a detector, and wherein detection is made such that multiple pass bands are allowed to be detected simultaneously.

Abstract: According to an example aspect of the present invention, there is provided a method for analysing a chemical composition of a target, the method comprising placing an electrically tunable Fabry-Perot interferometer in a path of radiation emitted by a radiation source, and detecting the radiation, which has passed the Fabry-Perot interferometer and which has passed or was reflected by the target, by means of a detector, and wherein detection is made such that multiple pass bands are allowed to be detected simultaneously.

Abstract: A method for determining spectral calibration data (?cal(Sd), Sd,cal(?)) of a Fabry-Perot interferometer (100) comprises: forming a spectral notch (NC2) by filtering input light (LB1) with a notch filter (60) such that the spectral notch (NC2) corresponds to a transmittance notch (NC1) of the notch filter (60), measuring a spectral intensity distribution (M(Sd)) of the spectral notch (NC2) by varying the mirror gap (dFP) of the Fabry-Perot interferometer (100), and by providing a control signal (Sd) indicative of the mirror gap (dFP), and determining the spectral calibration data (?cal(Sd), Sd,cal(?)) by matching the measured spectral intensity distribution (M(Sd)) with the spectral transmittance (TN(?)) of the notch filter (60).

Abstract: The present invention concerns an optical measurement system comprising an electrically tunable Peltier element, a detector for detecting radiation from a radiation source in a measurement area, the detector being in thermal connection with the Peltier element, an electrically tunable Fabry-Perot interferometer placed in the path of the radiation prior to the detector, the Fabry-Perot interferometer being in thermal connection with the Peltier element, and control electronics circuitry configured to control the Peltier element, the interferometer, and the detector. The present invention further concerns a method for analyzing the spectrum of an object.

Abstract: The present invention concerns a method for an optical measurement method including the following steps: illuminating an object by light, receiving light from the illuminated object to a tunable Fabry-Perot interferometer, changing mirror gap of the Fabry-Perot interferometer, and detecting the signal passed through the mirror gap of the Fabry-Perot interferometer at different gap lengths. In accordance with the invention the detection is performed at different lengths of times at different gap lengths.

Abstract: A device and a method for optical measurement of a target, wherein the target is irradiated with radiation beam (15) and a measurement beam (27) is received from the target and detected. Commonly used absorbance, reflectance and fluorescence measurements do not provide adequate information in e.g. measuring small contents of sulphur compounds. The present solution provides a new Raman spectrometer which is suitable for mass applications. A target is activated with pulses of a laser diode (12). The Raman signatures are measured and integrated successively with a point detector (44). A Fabry-Perot interferometer (42) on the measurement path is successively controlled into corresponding pass bands. While high spectral resolution or range is not required it is possible to use small-sized and low cost components.

Abstract: A method for determining spectral calibration data (?cal(Sd), Sd,cal(?)) of a Fabry-Perot interferometer (100) comprises: forming a spectral notch (NC2) by filtering input light (LB1) with a notch filter (60) such that the spectral notch (NC2) corresponds to a transmittance notch (NC1) of the notch filter (60), measuring a spectral intensity distribution (M(Sd)) of the spectral notch (NC2) by varying the mirror gap (dFP) of the Fabry-Perot interferometer (100), and by providing a control signal (Sd) indicative of the mirror gap (dFP), and determining the spectral calibration data (?cal(Sd), Sd,cal(?)) by matching the measured spectral intensity distribution (M(Sd)) with the spectral transmittance (TN(?)) of the notch filter (60).

Abstract: A method for determining spectral calibration data (?cal(Sd), Sd,cal(?)) of a Fabry-Perot interferometer (100) comprises: forming a plurality of filtered spectral peaks (P?1, P?2) by filtering input light (LB1) with a Fabry-Perot etalon (50) such that a first filtered peak (P?1) corresponds to a first transmittance peak (P1) of the etalon (50), and such that a second filtered peak (P?2) corresponds to a second transmittance peak (P1) of the etalon (50), using the Fabry-Perot interferometer (100) for measuring a spectral intensity distribution (M(Sd)) of the filtered spectral peaks (P?1, P?2), wherein the spectral intensity distribution (M(Sd)) is measured by varying the mirror gap (dFP) of the Fabry-Perot interferometer (100), and by providing a control signal (Sd) indicative of the mirror gap (dFP), and determining the spectral calibration data (?cal(Sd), Sd,cal(?)) by matching the measured spectral intensity distribution (M(Sd)) with the spectral transmittance (TE(?)) of the etalon (50).

Abstract: The invention relates to a Fabry-Perot interferometer and a method for producing the same. More specifically, the invention relates to Fabry-Perot interferometers which are controllable with one or several actuators, such as piezoelectric, electrostrictive or flexoelectric actuators. In prior art technology there is a problem to achieve a sufficiently small and uniform gap between mirrors. In the present invention an intermediate structure (85a, 85b, 95a, 95b, 81a, 81b, 91a, 91b, 98a, 98b) is used between a mirror and an actuator or between two mirrors. The method of production also includes measuring the width distribution of the gap in several phases, and providing pre-actuation of actuators.

Abstract: A device and a method for optical measurement of a target, wherein the target is irradiated with radiation beam (15) and a measurement beam (27) is received from the target and detected. Commonly used absorbance, reflectance and fluorescence measurements do not provide adequate information in e.g. measuring small contents of sulphur compounds. The present solution provides a new Raman spectrometer which is suitable for mass applications. A target is activated with pulses of a laser diode (12). The Raman signatures are measured and integrated successively with a point detector (44). A Fabry-Perot interferometer (42) on the measurement path is successively controlled into corresponding pass bands. While high spectral resolution or range is not required it is possible to use small-sized and low cost components.

Abstract: A method for producing a mirror plate for a Fabry-Perot interferometer includes providing a base slab, which includes a substrate coated with a reflective multilayer coating, forming one or more intermediate layers on the base slab such that the lowermost intermediate layer substantially consists of silica, and such that the multilayer coating is at least partially covered by the lowermost intermediate layer, forming one or more capacitive sensor electrodes by depositing conductive material on top of the intermediate layers, and removing material of the lowermost intermediate layer by etching in order to form an exposed aperture portion of the multilayer coating.

Abstract: The invention relates to a Fabry-Perot interferometer and a method for producing the same. More specifically, the invention relates to Fabry-Perot interferometers which are controllable with one or several actuators, such as piezoelectric, electrostrictive or flexoelectric actuators. In prior art technology there is a problem to achieve a sufficiently small and uniform gap between mirrors. In the present invention an intermediate structure (85a, 85b, 95a, 95b, 81a, 81b, 91a, 91b, 98a, 98b) is used between a mirror and an actuator or between two mirrors. The method of production also includes measuring the width distribution of the gap in several phases, and providing pre-actuation of actuators.

Abstract: A method for producing a mirror plate for a Fabry-Perot interferometer includes providing a base slab, which includes a substrate coated with a reflective multilayer coating, forming one or more intermediate layers on the base slab such that the lowermost intermediate layer substantially consists of silica, and such that the multilayer coating is at least partially covered by the lowermost intermediate layer, forming one or more capacitive sensor electrodes by depositing conductive material on top of the intermediate layers, and removing material of the lowermost intermediate layer by etching in order to form an exposed aperture portion of the multilayer coating.

Abstract: An imaging spectrometer includes a Fabry-Perot interferometer and an image sensor having color-sensitive pixels. The interferometer has a first transmission peak and a second transmission peak (PEAK2). A method calibrating the spectrometer includes providing first calibration light, which has a narrow spectral peak, obtaining first detector signal values from the image sensor by coupling the first calibration light into the spectrometer when the reference spectral peak is near a first spectral position, obtaining second detector signal values from the image sensor by coupling the first calibration light into the spectrometer when the reference spectral peak is near a second spectral position, providing second calibration light, which has a broad bandwidth, and obtaining third detector signal values from the image sensor by coupling the second calibration light into the spectrometer.

Abstract: An imaging spectrometer includes a Fabry-Perot interferometer and an image sensor having color-sensitive pixels. The interferometer has a first transmission peak and a second transmission peak (PEAK2). A method calibrating the spectrometer includes providing first calibration light, which has a narrow spectral peak, obtaining first detector signal values from the image sensor by coupling the first calibration light into the spectrometer when the reference spectral peak is near a first spectral position, obtaining second detector signal values from the image sensor by coupling the first calibration light into the spectrometer when the reference spectral peak is near a second spectral position, providing second calibration light, which has a broad bandwidth, and obtaining third detector signal values from the image sensor by coupling the second calibration light into the spectrometer.

Abstract: The invention relates to controllable Fabry-Perot interferometers which are produced with micromechanical (MEMS) technology. The prior art interferometers have a temperature drift which causes inaccuracy and requirement for complicated packaging. According to the invention the interferometer arrangement has both an electrically tuneable interferometer and a reference interferometer on the same substrate. The temperature drift is measured with the reference interferometer and this information is used for compensating the measurement with the tuneable interferometer. The measurement accuracy and stability can thus be improved and requirements for packaging are lighter.

Abstract: The invention relates to controllable Fabry-Perot interferometers which are produced with micromechanical (MEMS) technology. The prior art interferometers have a temperature drift which causes inaccuracy and requirement for complicated packaging. According to the invention the interferometer arrangement has both an electrically tuneable interferometer and a reference interferometer on the same substrate. The temperature drift is measured with the reference interferometer and this information is used for compensating the measurement with the tuneable interferometer. The measurement accuracy and stability can thus be improved and requirements for packaging are lighter.

Abstract: Data relating to the thickness of a thin film, for example, a thickness change is determined herein as follows. Said film is arranged onto a substrate so that said film and substrate form, in a whole, an interferometric structure. After that optical radiation is emitted towards the interferometric structure formed by the film and the substrate, and optically reflected from said interferometric structure radiation is measured. Said thin film thickness related data, for example, thickness change, is then determined by means of said optically reflected radiation, for example, of spectrum related information.

Abstract: A pressure measuring cell has a first housing body and a membrane arranged proximate the housing body, both of ceramic. The membrane has a peripheral edge joined to the first housing body to create a reference pressure chamber. A second housing body made of ceramic material is opposite the membrane and is joined to the peripheral edge of the membrane, the second housing body together with the membrane forming a measurement pressure chamber. The second housing body has a port for connecting the pressure measuring cell to a medium to be measured. The first housing body, the second housing body and the membrane are tightly connected along the peripheral edge of the membrane in a central area of the first housing body a hole is formed, reaching through the first housing body and at least in the central region of the membrane and opposite the hole a surface of the membrane is formed as a first optically reflective area.

Abstract: A pressure measuring cell has a first housing body and a membrane arranged proximate the housing body, both of ceramic. The membrane has a peripheral edge joined to the first housing body to create a reference pressure chamber. A second housing body made of ceramic material is opposite the membrane and is joined to the peripheral edge of the membrane, the second housing body together with the membrane forming a measurement pressure chamber. The second housing body has a port for connecting the pressure measuring cell to a medium to be measured. The first housing body, the second housing body and the membrane are tightly connected along the peripheral edge of the membrane in a central area of the first housing body a hole is formed, reaching through the first housing body and at least in the central region of the membrane and opposite the hole a surface of the membrane is formed as a first optically reflective area.