Abstract: A dual-comb spectrometer 5 with two lasers 10, 12 serving as a local oscillator and an interrogator. The lasers output light beams with respective frequency combs C1, C2 of defined free spectral range, FSR. A detector 30 can detect heterodyne mixing of the combined beams to detect an RF frequency comb C3. Respective control signals are supplied to the lasers which have functional forms configured to cause the frequencies of the lasers' frequency combs C1, C2 to tune over a defined fraction of their FSR. This enables a reduction of the effective spectral sampling period by a factor equal to the ratio of the FSR to the spectral resolution of the spectrometer, which will typically be several orders of magnitude, so that the spectral sampling period can be reduced from the GHz to the MHz range, which in turn enables a gapless spectrum to be obtained in a short time.

Abstract: A dual-comb spectrometer 5 with two lasers 10, 12 serving as a local oscillator and an interrogator. The lasers output light beams with respective frequency combs C1, C2 of defined free spectral range, FSR. A detector 30 can detect heterodyne mixing of the combined beams to detect an RF frequency comb C3. Respective control signals are supplied to the lasers which have functional forms configured to cause the frequencies of the lasers' frequency combs C1, C2 to tune over a defined fraction of their FSR. This enables a reduction of the effective spectral sampling period by a factor equal to the ratio of the FSR to the spectral resolution of the spectrometer, which will typically be several orders of magnitude, so that the spectral sampling period can be reduced from the GHz to the MHz range, which in turn enables a gapless spectrum to be obtained in a short time.

Abstract: A method and a system for detecting the presence of propellant gas in a gaseous sample exploit laser light especially in the 3.30-3.5 ?m range. The propellant can be propane, n-butane, i-butane, dimethyl ether, methyl ethyl ether, HFA 134a, HFA 227, or any other propellant exhibiting absorption in the requisite wavelength range. The presence of the application of this method in leak testing of propellant-containing containers such as aerosols or fuel canisters, permits high-speed, high accuracy leak detection capable of replacing existing testing methods.

Abstract: A Multi-pass optical cell (1) with an internal space (11) for laser spectroscopy is described, which is able to reduce or eliminate interference fringes appearing by performing laser absorption spectroscopy in the multi-pass optical cells (1) leading to improved absorption spectra. This is achieved by using a multi-pass optical cell (1) comprising an absorption mask (3) which is permanently or removable mountable in the internal space (11) in a rotatably fixed manner, where in a mask wall (30) a plurality of m apertures (300) is formed, in which the position of each aperture (300) is adapted to a predefinable propagation path of a main optical beam and/or the resulting reflection spot pattern (211) defined by the geometry of the multi-pass optical cell (1) and the used angle of incidence of an initial beam (20), so that each aperture (300) is traversable by the main optical beam from a first side (301) to a second side (302).

Abstract: A Multi-pass optical cell (1) with an internal space (11) for laser spectroscopy is described, which is able to reduce or eliminate interference fringes appearing by performing laser absorption spectroscopy in the multi-pass optical cells (1) leading to improved absorption spectra. This is achieved by using a multi-pass optical cell (1) comprising an absorption mask (3) which is permanently or removable mountable in the internal space (11) in a rotatably fixed manner, where in a mask wall (30) a plurality of m apertures (300) is formed, in which the position of each aperture (300) is adapted to a predefinable propagation path of a main optical beam and/or the resulting reflection spot pattern (211) defined by the geometry of the multi-pass optical cell (1) and the used angle of incidence of an initial beam (20), so that each aperture (300) is traversable by the main optical beam from a first side (301) to a second side (302).

Abstract: A method and a system for detecting the presence of propellant gas in a gaseous sample exploit laser light especially in the 3.30-3.5 ?m range. The propellant can be propane, n-butane, i-butane, dimethyl ether, methyl ethyl ether, HFA 134a, HFA 227, or any other propellant exhibiting absorption in the requisite wavelength range. The presence of the application of this method in leak testing of propellant-containing containers such as aerosols or fuel canisters, permits high-speed, high accuracy leak detection capable of replacing existing testing methods.