Abstract: This invention relates to retrievable measuring cell for optical measurements in gas, the cell being defined by a gas conducting pipe having an input end adapted to be connected to a gas flow input intruding gas into the cell and an output end adapted to be connected to a gas flow output. The pipe ends also being adapted to be coupled to optical components including an optical transmitter transmitting light into said cell and an optical receiver adapted to receive light having passed through said cell, the optical beam in said cell having a predetermined shape, the optical components including a light source, at least two minors and a light receiver being mounted in known positions on an external frame covered by the pipe ends. The cell has an elongated shape corresponding to the optical beam shape.

Abstract: This invention relates to retrievable measuring cell for optical measurements in gas, the cell being defined by a gas conducting pipe having an input end adapted to be connected to a gas flow input intruding gas into the cell and an output end adapted to be connected to a gas flow output. The pipe ends also being adapted to be coupled to optical components including an optical transmitter transmitting light into said cell and an optical receiver adapted to receive light having passed through said cell, the optical beam in said cell having a predetermined shape, the optical components including a light source, at least two minors and a light receiver being mounted in known positions on an external frame covered by the pipe ends. The cell has an elongated shape corresponding to the optical beam shape.

Abstract: The present invention relates to a Fabry-Perot interferometer including two plane mirror surfaces mounted in a frame and a system including the interferometer. The mirrors have a known distance between them, and at least one of the mirror surfaces is both partially reflective and partially reflective, where there are at least two actuator units, each including at least one actuator. The first actuator unit is adapted to adjust said distance between said mirrors and the second actuator unit is adapted to modulate said distance at a chosen frequency, both thus providing a variation over a range of mirror distances corresponding to a range of filtered wavelengths in said Fabry-Perot interferometer. At least one of said mirrors is related to the frame through a silicon membrane, at least one of said actuator units comprising a piezoelectric material on said membrane, thus constituting a bimorph or unimorph actuator unit.

Abstract: The present invention relates to a Fabry-Perot interferometer including two plane mirror surfaces mounted in a frame and a system including the interferometer. The mirrors have a known distance between them, and at least one of the mirror surfaces is both partially reflective and partially reflective, where there are at least two actuator units, each including at least one actuator. The first actuator unit is adapted to adjust said distance between said mirrors and the second actuator unit is adapted to modulate said distance at a chosen frequency, both thus providing a variation over a range of mirror distances corresponding to a range of filtered wavelengths in said Fabry-Perot interferometer. At least one of said mirrors is related to the frame through a silicon membrane, at least one of said actuator units comprising a piezoelectric material on said membrane, thus constituting a bimorph or unimorph actuator unit.