Abstract:
A light beam generated by a light source having a wavelength corresponding to the ethanol absorption spectrum, preferably in the wavelength range of 3.28-3.52 μm or in one or more wavelength ranges 6.49-7.46 μm, 7.74-8.33 μm, 8.84-10.10 μm, 10.7-12.00 μm, is sent through a measuring space containing a sample of exhaled breath, and then the intensity of the light beam passing through the measuring space is measured. Based on the spectral analysis of the dependence of the light intensity to the alcohol concentration, the concentration of ethanol vapor is determined and the information about the level of the ethanol content is provided to a suitable display or device.
Abstract:
A method for reducing fringe interference of light created in a passive cavity defined by partially reflecting optical surfaces in a laser spectroscopy system, wherein the optical path length of the cavity is varied with a triangular back-and-forth movement (x). In accordance with the invention, the spectroscopic measurement is performed in successive measurement cycles with a time interval between each two successive measurement cycles, the triangular movement is performed such that the turning points of the triangular movement (x) are positioned in successive ones of the time intervals, and after each or at each n-th measurement cycle, the time position of the turning points is moved relative to the measurement cycle.
Abstract:
A method for reducing fringe interference of light created in a passive cavity defined by partially reflecting optical surfaces in a laser spectroscopy system, wherein the optical path length of the cavity is varied with a triangular back-and-forth movement (x). In accordance with the invention, the spectroscopic measurement is performed in successive measurement cycles with a time interval between each two successive measurement cycles, the triangular movement is performed such that the turning points of the triangular movement (x) are positioned in successive ones of the time intervals, and after each or at each n-th measurement cycle, the time position of the turning points is moved relative to the measurement cycle.
Abstract:
A method for reducing fringe interference of light created in a passive cavity defined by partially reflecting optical surfaces, wherein the optical path length of the cavity is varied with a Gaussian distribution, where the standard deviation is at least one-quarter of the light's wavelength.