Abstract: An IR microscope includes an IR light source/interferometer (1) generating a collimated IR beam (26), an effectively beam-limiting element (8) in a stop plane (27), a sample position (15), a detector (19) having an IR sensor (19a), a detector stop (19b), a first optical device focusing the collimated IR beam onto the sample position, and a second optical device imaging the sample position onto the IR sensor. The effectively beam-limiting element is situated in the collimated IR beam. The first and second optical devices image the detector stop opening into an input beam plane. For the area A1 of the image of the detector stop opening in the input beam plane and the area A2 of the cross section of the collimated IR beam in the input beam plane: 0<A1/A2?1. Thereby, only collimated IR radiation is picked up, while vignetting and stray radiation are avoided.

Abstract: A method for determining a correcting quantity function kF(x, y) for calibrating an FTIR measurement arrangement with an IR detector. The IR detector includes a plurality of sensor elements, which are each located at a position (x, y), and the method includes: (a) recording interferograms IFGRxy of a reference sample using the sensor elements of the IR detector, (b) calculating spectra Rxy of the reference sample by Fourier transforming the interferograms of the reference sample for at least four sensor elements, (c) calculating correcting quantities kxy by comparing each spectrum Rxy of the reference sample calculated in step b) with a reference data set of the reference sample, and (d) determining the correcting quantity function kF(x, y) using the correcting quantities kxy calculated in step c). This permits frequency shifts that occur in FTIR spectrometers with extensive detectors to be effectively corrected regardless of the position of the sensor element.

Abstract: An IR microscope includes an IR light source (1) generating a collimated IR beam (26), an effectively beam-limiting element (8) in a stop plane (27), a sample position (15), a detector (19) having an IR sensor (19a), a detector stop (19b), a first optical device focusing the collimated IR beam onto the sample position, and a second optical device imaging the sample position onto the IR sensor. The effectively beam-limiting element is situated in the collimated IR beam. The first and second optical devices image the detector stop opening into an input beam plane. For the area A1 of the image of the detector stop opening in the input beam plane and the area A2 of the cross section of the collimated IR beam in the input beam plane: 0<A1/A2?1. Thereby, only collimated IR radiation is picked up, while vignetting and stray radiation are avoided.

Abstract: A measuring cell for a gas analysis spectrometer has an inner chamber for a sample gas to be analyzed and an inlet and an outlet which are connected thereto. A traversing optical path for a measuring beam is formed in the inner chamber. The measuring cell is tubular, the inlet and the outlet are arranged at opposite ends, and the inner chamber of the measuring cell has a cross-sectional shape that is monotonic over the length of the tube and which has an oval-shape at the start, which disappears toward the end. That special shape results in fast gas exchange and thus high dynamics, even with larger measuring cells, which have high sensitivity due to the long optical paths thereof. Two characteristics which until now appeared to be conflicting are thereby combined.

Abstract: A method for the acquisition (AU) of a spectrally resolved, two-dimensional image by means of Fourier transform (FT) spectroscopy or Fourier transform infrared (FTIR) spectroscopy, is characterized in that, during multiple passes (D1-D4) of an optical path difference (OG) between two partial rays (14a, 14b) over an identical range (IB), different subsets of detector elements (22) of an array detector (5) are read out and the signals of the read-out detector elements (22) of the multiple passes (D1-D4) are Fourier transformed and combined to form the spectrally resolved image. A method is thereby provided for the acquisition of two-dimensional, spectrally resolved images, in which the influence of vibrations on the measurement is reduced, and which is less affected by the movement of objects to the resolved spectrally.

Abstract: A measuring cell for a gas analysis spectrometer has an inner chamber (23) for a sample gas to be analyzed and an inlet (21) and an outlet (22) which are connected thereto. A traversing optical path for a measuring beam (14) is formed in the inner chamber (23). The measuring cell is tubular, the inlet (21) and the outlet (22) are arranged at opposite ends, and the inner chamber (23) of the measuring cell has a cross-sectional shape that is monotonic over the length of the tube and which has an oval-shape at the start, which disappears toward the end. That special shape results in fast gas exchange and thus high dynamics, even with larger measuring cells, which have high sensitivity due to the long optical paths thereof. Two characteristics which until now appeared to be conflicting are thereby combined.

Abstract: A measuring cell for a gas analysis spectrometer has an inner chamber (23) for a sample gas to be analyzed and an inlet (21) and an outlet (22) which are connected thereto. A traversing optical path for a measuring beam (14) is formed in the inner chamber (23). The measuring cell is tubular, the inlet (21) and the outlet (22) are arranged at opposite ends, and the inner chamber (23) of the measuring cell has a cross-sectional shape that is monotonic over the length of the tube and which has an oval-shape at the start, which disappears toward the end. That special shape results in fast gas exchange and thus high dynamics, even with larger measuring cells, which have high sensitivity due to the long optical paths thereof. Two characteristics which until now appeared to be conflicting are thereby combined.