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: 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).