Abstract:
Embodiments relate generally to electromagnetic radiation detector devices, systems, and methods using a planar Golay cell. One device includes a cell body forming a cavity therein, wherein the cavity includes a wavelength selective absorber having a predetermined absorption spectral range and the cavity is filled with a gas and a pressure sensing element fluidly connected to the cavity to measure a change in pressure within the cavity. One device may include a plurality of planar Golay cells, wherein the cell bodies of the Golay cells are stacked against one another, wherein the pressure sensing elements of the Golay cells are located adjacent to the stacked sides of the cell bodies, and wherein radiation from a single light source is directed through the plurality of Golay cells.
Abstract:
A measuring instrument for simultaneous in situ determination of the spectral scatting and absorption coefficient, which can also be called an extinction meter, has a modulated light source and an optical system encompassing the hemisphere; the optical system has a multiply folded ray path with a focal point in the volume to be measured, and through this system the measurement signal is projected to detectors. The scattering measurement signals, which are maximally enlarged in this way, are then separated from those for the absorption. The extinction meter also has not only an integrating nephelometer for monitoring purposes but also a transmission meter for low transmission factors. Because of the small three-dimensional size and the streamlined shape of the measuring portion of the extinction meter, the extinction meter can be carried in aircraft and surface vehicles. Because of the disposition of the optical system, the error in the measurement values is negligible, in comparison with other instruments with which only the scattering coefficient can be determined. Moreover, the calibration value during a measurement phase can be determined both automatically and manually. Contamination of the instrument with gas to be measured is reduced, by the stabilization of a turbulence ring by means of baffles. Moreover, interference with the flowing aerosol on the part of the instrument is largely eliminated via a hoop-like hood functioning like a wing-tip slot.
Abstract:
A gas cell array absorbs infrared energy radiated by a viewed scene. A la interferometer has its resultant intensity changed by the cell's changing length. This is monitored by a vidicon tube that feeds the signal to a digitizer and onto a video display. The incident infrared radiation is chopped into quantized amounts of energy and memory units receive the digitized output of the vidicon tube. Subtractors receive vidicon tube signals simultaneously with quiescent reference levels data. The subtractors form a difference signal by subtracting the quiescent reference level signal from the immediate signal being passed to control threshold detectors. An extended dynamic range of 1,000:1 is accomplished for the preferred embodiment.
Abstract:
The present invention relates to ellipsometer and polarimeter systems, and more particularly is an ellipsometer or polarimeter or the like system which operates in a frequency range between 300 GHz or lower and extending to higher than at least 1 Tera-hertz (THz), and preferably through the Infra-red (IR) range up to, and higher than 100 THz, including: a source such as a backward wave oscillator; a Smith-Purcell cell; a free electron laser, or an FTIR source and a solid state device; and a detector such as a Golay cell; a bolometer or a solid state detector; and preferably including at least one odd-bounce polarization state image rotating system, and optionally including a polarizer, at least one compensator and/or modulator, in addition to an analyzer.
Abstract:
A flame sensor comprises a cell (10) containing an infra-red absorptive fluid such as carbon dioxide gas. Heating caused by absorption of the infra-red radiation is detected by measuring a resulting temperature or pressure change.
Abstract:
A device for optically displaying thermal image scenes, comprising pneumatic infrared sensors, for example, temperature-sensitive gas cells. A mosaic of thermal IR sensors, which is arranged on an infrared-transparent plate and which picks up the thermal image scene, is arranged in front of a reference plate whose inclination can be adjusted and which is irradiated by optical light. The interference patterns produced are picked up by an optical system. Thermal drift is suppressed by providing the IR sensors in a hermetically sealed chamber.
Abstract:
Electromagnetic radiation is detected, using a photoacoustic cell employing a uniform absorber of radiation which absorbs independently of wavelength.
Abstract:
A calorimeter for measuring high-energy pulsed laser light. The light is absorbed by a suitable liquid which causes a molecular expansion. The liquid may be permitted to expand and the change of volume may be measured by a capillary tube. Alternatively, if the liquid is not permitted to expand, the rising pressure may be measured. This obviates the usual waiting period needed for a temperature equilibrium to be reached in conventional calorimeters.