Abstract: This invention relates to an optical displacement sensor element, e.g. for use in a pressure sensor or a microphone, comprising two essentially flat surfaces being separated by a cavity being defined by a spacer, the distance between the surfaces being variable thus providing a displacement sensitive Fabry-Perot interferometer. Both or said surfaces are at least partially reflective, and in that said first surface is provided with at least one optical detector, and one of surfaces being provided on an at least partially transparent material.

Abstract: A spring scale, in particular for weighing loads in the ?g-mg range, comprises a load platform suspended by at least three flexural springs in a surrounding frame, and has bridge-connected strain gauges arranged for measuring strain on one side of the flexural springs. The flexural springs extend in succession along substantially the whole periphery of the load platform in a gap between the load platform and the inner edge of the frame, and an attachment spot on the load platform for every flexural spring is arranged substantially directly opposite or past an attachment spot on the inner edge of the frame for a next flexural spring in the succession of springs. Preferably, the of spring scale is made in one piece, and manufactured by means of semiconductor process technology.

Abstract: A sensor for monitoring gas content. The sensor comprises a housing defining at least two cavities and a resonating structure positioned in each of the cavities. Each of the resonating structures has a resonant frequency dependent upon a physical characteristic of a gas in its respective cavity. Means for exciting the resonating structures generates output signals therefrom, and means compares the output signals from each of the resonating structures and outputs a comparison signal indicative of a difference between the resonant frequencies of the two structures and the relative gas content of the at least two cavities.

Abstract: A line of sight laser communication system includes a laser to generate a laser signal with femtosecond pulses. A first grating spectrally disperses the femtosecond pulses of the laser signal. A programmable mask converts the femtosecond pulses of the laser signal into coded words. A second grating spectrally recombines the coded words of the laser signal. A telescope then launches the laser signal. The launched laser signal is received at a receiving telescope. A second laser generates a set of reference pulses. A non-linear crystal combines the set of reference pulses and the laser signal to create an output signal only when the laser signal and the reference pulses temporally coincide. A camera records the output signal.

Abstract: A laser communication system includes a first laser to generate a laser signal with femtosecond pulses. A first grating spectrally disperses the femtosecond pulses of the laser signal. A modulator converts the femtosecond pulses of the laser signal into coded words. A second grating spectrally recombines the coded words of the laser signal. A first telescope launches the laser signal. A second telescope receives the laser signal. A second laser generates a set of reference pulses. A non-linear crystal combines the set of reference pulses and the laser signal so as to create an output signal only when the laser signal and the reference pulses temporally coincide. A detector records the output.

Abstract: Photo acoustic infrared (IR) detector including a chamber for receiving a gas or gas mixture, a window for allowing pulsed or modulated IR radiation into the chamber, and a pressure sensor adapted to measure pressure changes in the chamber as a consequence of absorbed IR radiation. A generally plate-shaped main part has a recess or bore for substantially forming the chamber whereby the window closes the chamber at one side of the main part and whereby the pressure sensor is of the miniature type and is located at the opposite side of the main part in relation to said one side so that the pressure sensor communicates with and closes the chamber at the opposite side, except for a venting channel for the chamber. A cap is provided at said opposite side of the main part so that it encloses the pressure sensor and forms a gas space communicating with the chamber through the venting channel and being substantially larger than the gas volume in the chamber.

Abstract: A laser communication system includes a first laser to generate a laser signal with femtosecond pulses. A first grating spectrally disperses the femtosecond pulses of the laser signal. A modulator converts the femtosecond pulses of the laser signal into coded words. A second grating spectrally recombines the coded words of the laser signal. A first telescope launches the laser signal. A second telescope receives the laser signal. A second laser generates a set of reference pulses. A non-linear crystal combines the set of reference pulses and the laser signal so as to create an output signal only when the laser signal and the reference pulses temporally coincide. A detector records the output.

Abstract: A photoacoustic detector including a chamber (1) for receiving the gas, a path for pulsed or modulated IR radiation (2) into, through and out of the chamber, and a pressure sensor (3A-B) adapted to measure pressure changes in the chamber caused by the applied IR radiation. The chamber is formed by joining together at least two major semiconductor elements, in particular, silicon or quartz elements (4A-B) made in planar technology. At least a first element from a major surface (9A-B) has an etched recess which constitutes a substantial proportion of the volume of the chamber. At least one of the elements is provided with a membrane for the pressure sensor, and the space (7) in front of the membrane communicates with the chamber.

Abstract: Method and apparatus are presented for snaring explosive, combustible, and other hazardous compounds in vapor and in particulate form, and also combustion residues, which system can be used to prevent, or retrodict the cause of explosions, fires, etc. after they have occurred. The snares are in the form of gated chambers on rotating time disks and moving belts which are used to capture molecules and particulate matter. The combination detects hazardous molecules and combustible particles or causes of dust explosions; and indicates an approximate time-history record of the evolution of particles before or during the course of fires and explosions, or other onerous occurances.