US Government as Represented by the Secretary of the Army

John J Ehrlich

Thomas A Barr, Jr

Travis S Taylor

Wayne E Davenport

This invention provides a means for detecting local atmospheric contaminants from safe distances. The invention means of a detector system comprise a pulsed laser, a sensitive photo-detector, various optical filters, and necessary digital control circuitry. The detector system employs laser technology in combination with a sensitive photo-detector to achieve detection of any hazardous gas elements or other pollutants remotely located from personnel who may subsequently be exposed. In operation, a pulsed laser or a tunable dye laser is employed as an excitation source for the contaminant or pollutant to achieve excitation of the contaminant or pollutant. When the excited molecule of the contaminant or pollutant returns to ground-state it emits a photon at a given (measurable) frequency. A sensitive photo-detector is filtered to permit detection of only the frequency at which a harmful gas (as an example of a contaminant or pollutant) fluoresces. Various filters can be utilized at once to enable the detector to detect more than one pollutant at a time. A timer in the system determines time elapse from the time the laser is pulsed to the time a photon is detected, the location of the gas pollutant can then be determined. Similarly, by relating distance and intensity of fluorescence via the detector, the density of the gas pollutant in the local atmosphere can be determined. The entire system is controlled by simple compact digital technology.

Atmospheric contaminant detector

The structure of this invention provides a means for shielding an optically ensitive detector, device, or components from electromagnetic fields without shielding them from the optical spectra desired to be transmitted. The structure of the invention is in the form of an optically transmissive Faraday cage or box having optically transparent material selected from optical glass and optically transparent plastic which functions as a substrate. The substrate is provided a thin film of predetermined skin depths in the form of a conductive coating selected from silver and a nickel-chromiumiron-manganese-silicon-copper-alloy. The conductive coating is applied in a thickness equivalent to a predetermined number of skin depths in order to attenuate an external electromagnetic field strength to meet the tolerance of the detector, device, or components which are to be shielded.

Optically transmissive Faraday cage

A continuous wave chemical laser device in which useful species such as free radicals as vibrationally excited molecules are generated by interaction of suitable chemicals such as hydrogen, sulfur hexafluoride, and carbon dioxide with laser radiation. The chemical laser device is capable of generating active species by interaction of its own laser radiation after first being initiated by a suitable initiator. The chemical reactions involved can take place at atmospheric pressure or higher and overcome disadvantages of ordinary chemical lasers.

Chemical laser from radiative decomposition of chemicals

Method for producing continuous wave chemical laser output in which useful species such as free radicals as vibrationally excited molecules are generated by interaction of suitable chemicals such as hydrogen, sulfur hexafluoride, and carbon dioxide with initiator laser radiation. The chemical laser output is sustained by feeding back a portion of the laser output after first being initiated by a suitable initiator. The chemical reactions involved can take place at atmsopheric pressure or higher and overcome disadvantages of ordinary chemical lasers.

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Huntsville, AL, United States of America

John J Ehrlich