USA As Represented by Secretary of the Navy

Terence W Barrett

John F Giuliani

In an external lasing dye sensor system, a stream of lasing dye free-flows cross an open area inside a chamber. An air sample comprising chemical vapor contaminants is pumped or drawn into the chamber. A laser beam is introduced into the chamber intersecting the lasing dye. A chemical reaction between the contaminants and the lasing dye result in a change in the emission spectra of the lasing dye. The change in emission spectra is detected and thus provides an improved apparatus for detecting low concentrations of chemical vapors in an air sample.

Lasing dye sensor for chemical vapors

In a lasing dye sensor system, a stream of lasing dye freeflows across an ea open to the atmosphere. A chemical reaction between contaminants in the atmosphere and the lasing dye result in the change of emission spectra of the lasing dye. The change in emission spectra is detected and provides an improved apparatus and method for detecting low concentrations of chemical vapors in the atmosphere.

Method for detecting chemical vapors using a lasing dye sensor

A laser for generating a coherent output beam with a frequency equal to the um or difference of the frequencies of two input pumping beams or the harmonics thereof. The laser includes a lasing medium of the type with an inverse Faraday effect resonance frequency f.sub.1, a laser cavity with the lasing medium positioned therein, two coherent light sources for generating pumping beams at frequency f.sub.1 and f.sub.2, where the f.sub.1 beam is circularly polarized, and an optical system for directing the pumping beams into the lasing medium.

Magnetically induced laser

An optical device for obtaining a 3-dimensional signature or a plurality of 2-dimensional signatures for a given sample in order to detect predetermined chemical agents. The device comprises a light channel with a first sensing optical fiber with a coating thereon which changes its absorptive and refractive properties in the presence of a predetermined chemical agent, and a second light channel with a reference optical fiber isolated from the sample. A scanning monochromator is utilized to apply light beams to the sensing and reference fibers, and an optical detector is used to cross-correlate the outputs from the sensing and reference fibers. A variable optical delay line is disposed in one of the fiber channels in order to scan from 0.degree. to 360.degree. in phase shift for each light frequency. A 2-dimensional cross-correlation is obtained for this scan at this frequency. The scanning monochromator is set to run through a series of light frequencies in a given bandwidth. A 2-dimensional cross-correlation phase scan is obtained at each different light frequency. A 3-dimensional cross-correlation may then be obtained (cross-correlation value vs frequency vs phase delay) to provide a signature for a given sample which can be compared to known samples. The device may utilize separate channel bandwidth filters to obtain squeezed states and high S/N ratios.

Optical 3-d signature device for detecting chemical agents

A method and apparatus for detecting the wavelength of singlet state resonance fluorescence of a sample, wherein the sample is illuminated sequentially with various incident wavelengths. For each wavelength, linearly polarized and circularly polarized components are allowed to pass sequentially by a first polarizer to the sample. The sample emits light as a result of spontaneous molecular energy transitions. Four components of the emitted light are allowed to sequentially pass to a detector by a second polarizer. The intensities of these components are then detected, and these values can be employed to obtain a new ratio for each wavelength. The wavelength at which this ratio equals one is selected as the wavelength of resonance fluorescence. In one example, a computer is provided to control the illumination of the sample and the two polarizers, and also may be utilized to compute the above ratios.

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Bethesda, MD, United States of America

Terence W Barrett