| abstract |
The invention relates to a device for analyzing a substance, comprising: - a measurement body (1, 1a), which has a measurement surface (2) and is to be brought at least in part into contact with the substance (3) in the region of the measurement surface for the purpose of measuring; a laser device (4), particularly having a quantum cascade laser (QCL), a tunable QCL and/or a laser array, preferably an array of QCLs, in order to generate one or more excitation beams (10) at different wavelengths, preferably in the infrared or medium infrared spectral range, which is directed to the substance (3); and a detection apparatus (5, 6, 7) which is integrated at least in part in the measurement body (1, 1a) or connected thereto and comprises the following: • a source (5) for coherent detection light (11) and • a first optical waveguide structure (6) which can be or is connected to the source for the detection light, which guides the detection light, and has a refractive index which is dependent at least in portions on the temperature and/or pressure, wherein the first optical waveguide structure has at least one portion (9) in which the light intensity depends on a phase shift of detection light in at least one part of the first optical waveguide structure (6) due to a change in temperature or pressure. |