Abstract: The invention relates to determining a polarization dependent property of an optical device under test, wherein a response signal is received from the device under test in response to an optical stimulus signal having an reference state of polarization, an output state of polarization of the response signal is determined, a reference information about the reference state of polarization is received, the reference state of polarization is determined on the base of the reference information and a predefined function describing the dependency of reference information versus the reference state of polarization, and the polarization dependent property is determined on the base of the reference state of polarization and the output state of polarization.

Abstract: The invention relates to determining a polarization dependent property of an optical device under test, wherein a response signal is received from the device under test in response to an optical stimulus signal having an reference state of polarization, an output state of polarization of the response signal is determined, a reference information about the reference state of polarization is received, the reference state of polarization is determined on the base of the reference information and a predefined function describing the dependency of reference information versus the reference state of polarization, and the polarization dependent property is determined on the base of the reference state of polarization and the output state of polarization.

Abstract: A laser system includes a gain medium for providing and amplifying a laser beam within an optical resonator. According to the invention, the laser system actively provides a plurality of different optical modes for stabilizing the laser beam, preferably by forcing the laser beam to jump between different optical modes more frequent than environmental disturbances occur. Providing the plurality of different optical modes can be achieved e.g. by varying the phase of the laser beam and/or by varying the optical length of the optical resonator. The laser system can be employed in a gas monitoring system, e.g. for monitoring a respiration and/or anaesthetic gas, for providing a Raman spectrum of the gas to be monitored.

Abstract: Disclosed is the determining of a composition of a gas mixture comprising an amount of one or more noble gases. A Raman spectrum of the gas mixture is measured first, and the amount(s) of Raman-active gas(es) in the gas mixture are determined based on the measured Raman spectrum. The amount of the (Raman non-active) one or more noble gases in the gas mixture can then be determined from the determined amount(s) of Raman-active gas(es). The composition of the gas mixture can also be determined by analyzing the Raman scattering in combination with the Rayleigh scattering. Based on the measured Raman spectrum, the expected intensifies of the Rayleigh lines of the Raman-active gases in the gas mixture are determined. The amount of the noble gas in the gas mixture is represented by the difference of the summed up Rayleigh lines of the Raman-active gases to the Rayleigh line in the measured spectrum.

Abstract: Method for preparing a laser cavity resonator for use in a Raman gas analyzer, that resonator comprises a V-shaped housing which comprises a first and a second channel for the laser beam in a V-arrangement. The method allows the adjustment of the resonator in the manufacturing site and provides a high mechanical stability and reliability of the system and accelerates the manufacturing of the resonator. The resonator received by the method comprises adjusted mirrors fixed to the housing so that the resonator can be transported and installed in the analysis system at its place of application.

Abstract: Method and arrangement for adjusting a mirror to a laser resonator such that the light impinging on said mirror is reflected on itself. A laser beam of an auxiliary gas laser circulates between the mirror to be adjusted and the output coupler mirror of the gas laser. A part of the laser beams reflected by the mirror is decoupled and projected as different light dots on a ground glass screen. By micro positioning of the mirror the different light dots are fused together to one light dot so that the light impinging on the mirror is reflected back on itself. The method and the arrangement allow a fast and exact adjustment of the mirror which further can be easily automated.

Abstract: An improved optical probe for the invasive measurement of blood parameters is disclosed that minimizes reading inaccuracy due to mechanical stresses. An optical probe for the invasive measurement of blood parameters is typically made up of various sensors that end in a sheath. Each sensor is connected to a monitor via an optical fiber. The optical fibers are surrounded by a tube. In the region where the sheath adjoins the tube, the sheath is deformed by crimping such that a better mechanical contact (form-locking) between the sheath, the sensors, and the tube can be obtained, in order to avoid systemic errors caused by displacement of the optical fibers inside the sheath.

Abstract: An improved optical probe for the invasive measurement of partial carbon dioxide pressures is disclosed that minimizes pCO.sub.2 reading drift. An optical probe for the invasive measurement of the partial carbon dioxide pressure comprises an optical fiber and a pCO.sub.2 sensor. The pCO.sub.2 sensor comprises a diffusion zone with a dye-containing gel that is optically sensitive to H.sup.+ ions and a semi-permeable membrane that is permeable to CO.sub.2 molecules, but is substantially nonpermeable to hydrogen ions Components of the pCO.sub.2 sensor, such as the part of the optical fiber extending into the sensor or a reflector, are covered with a substance--preferably with a coating--that is substantially nonpermeable to hydrogen ions. This prevents the hydrogen ions from diffusing into the sensor components, which otherwise would cause an imbalance of hydrogen ions and, therefore, a drift in the pCO.sub.2 reading.

Abstract: Polyacrylamide gels containing bound dye indicator molecules being sensitive to pH variation are treated with an aqueous solution for a period of time until the shifting of the pK value of the gel, due to the treatment, has finished.