Abstract: An apparatus for detection and measurement of trace species in a gas or liquid sample. A sensor of a ring down cell formed from an optical fiber is exposed to the sample gas or liquid. A coherent source emits radiation into the optical fiber loop, which in turn is received at an output coupler. The fiber optic ring is coupled to a sensor which has a portion thereof, between the input and output, exposed to the sample gas or sample liquid. The sensor has an enhanced evanescent region. A processor is coupled to the receiver and determines the level of trace species in the gas or liquid sample based on the rate of decay of the radiation within the fiber optic ring.

Abstract: A method for detection and measurement of trace species in a gas or liquid sample is provided. The method comprises forming a sensor from an optical fiber by tapering a portion the optical fiber along a length thereof, exposing the tapered portion of the optic fiber to the sample gas or sample liquid, emitting radiation from a coherent source, coupling at least a portion of the radiation emitted from the coherent source into the fiber optic ring, receiving a portion of the radiation traveling in the fiber optic ring, and determining the level of trace species in the gas or liquid sample based on a rate of decay of the radiation within the fiber optic ring.

Abstract: An apparatus for detection and measurement of trace species in a gas or liquid sample. A sensor of a ring down cell formed from an optical fiber is exposed to the sample gas or liquid. A coherent source emits radiation into the optical fiber loop, which in turn is received at an output coupler. The fiber optic ring is coupled to a sensor which has a portion thereof, between the input and output, exposed to the sample gas or sample liquid. The sensor has an enhanced evanescent region. A processor is coupled to the receiver and determines the level of trace species in the gas or liquid sample based on the rate of decay of the radiation within the fiber optic ring.

Abstract: An apparatus for detection and measurement of trace species in a gas or liquid sample. A sensor of a ring down cell formed from an optical fiber is exposed to the sample gas or liquid. A coherent source emits radiation into the optical fiber loop, which in turn is received at an output coupler. The fiber optic ring is coupled to a sensor which has a portion thereof, between the input and output, exposed to the sample gas or sample liquid. The sensor has an enhanced evanescent region. A processor is coupled to the receiver and determines the level of trace species in the gas or liquid sample based on the rate of decay of the radiation within the fiber optic ring.

Abstract: A method for detection and measurement of trace species in a gas or liquid sample is provided. The method comprises forming a sensor from an optical fiber by tapering a portion the optical fiber along a length thereof, exposing the tapered portion of the optic fiber to the sample gas or sample liquid, emitting radiation from a coherent source, coupling at least a portion of the radiation emitted from the coherent source into the fiber optic ring, receiving a portion of the radiation traveling in the fiber optic ring, and determining the level of trace species in the gas or liquid sample based on a rate of decay of the radiation within the fiber optic ring.

Abstract: An apparatus for detection and measurement of trace species in a gas or liquid sample. A ring down cell formed from a fiber optic ring is exposed to the sample gas or liquid. A coherent source emits radiation into the fiber optic ring, which in turn is received at an output thereof. The fiber optic ring has a portion thereof, between the input and output, exposed to the sample gas or sample liquid. A processor is coupled to the receiver and determines the level of trace species in the gas or liquid sample based on the rate of decay of the radiation within the fiber optic ring.

Abstract: A novel system and method for data reduction for improved exponential decay rate measurement in the present of excess low frequency noise. The system and method fit the tail of a record to a straight line wherein the straight line is extrapolated to the entire record and then subtracted from the initial data points before a logarithmic transformation is taken.

Abstract: An apparatus for measurement of strain in a material. The apparatus comprises a passive fiber optic ring; at least one sensor having a predetermined shape and in line with the fiber optic ring, the at least one sensor coupled to the substrate; coupling means for i) introducing a portion of radiation emitted by the coherent source to the passive fiber optic ring and ii) receiving a portion of the radiation resonant in the passive fiber optic ring; a detector for detecting a level of the radiation received by the coupling means and generating a signal responsive thereto; and a processor coupled to the detector for determining a level of the strain inducing into the substrate based on a rate of decay of the signal generated by the detector.

Abstract: An apparatus for detection and measurement of trace species in a gas or liquid sample. A ring down cell formed from a fiber optic ring is exposed to the sample gas or liquid. A coherent source emits radiation into the fiber optic ring, which in turn is received at an output thereof. The fiber optic ring has a portion thereof, between the input and output, exposed to the sample gas or sample liquid. A processor is coupled to the receiver and determines the level of trace species in the gas or liquid sample based on the rate of decay of the radiation within the fiber optic ring.

Abstract: An apparatus for detection and measurement of trace species in a gas or liquid sample. A sensor of a ring down cell formed from an optical fiber is exposed to the sample gas or liquid. A coherent source emits radiation into the optical fiber loop, which in turn is received at an output coupler. The fiber optic ring is coupled to a sensor which has a portion thereof, between the input and output, exposed to the sample gas or sample liquid. The sensor has an enhanced evanescent region. A processor is coupled to the receiver and determines the level of trace species in the gas or liquid sample based on the rate of decay of the radiation within the fiber optic ring.

Abstract: A novel system and method for data reduction for improved exponential decay rate measurement in the present of excess low frequency noise. The system and method fit the tail of a record to a straight line wherein the straight line is extrapolated to the entire record and then subtracted from the initial data points before a logarithmic transformation is taken.

Abstract: A stable resonator for a ring-down cavity spectroscopy cell having an optic axis. The resonator includes two Brewster's angle retroreflector prisms, each having a plurality of total internal reflection surfaces, with one of the total internal reflection surfaces of at least one of the prisms having a curved surface (either a ground curved surface or a surface curved by the addition, through optically contacting or gluing, of a plano-convex lens to the surface). The prisms are disposed in alignment along the optic axis of the resonator. A spherical mirror or lens, tilted from normal incidence to produce a desired degree of astigmatism, mode matches the radiation into the resonator. One or both of the prisms can be rotated so that light rays enter and leave a surface of the prism nearly at Brewster's angle to the normal of the prism surface. This feature maintains alignment between the prisms and allows the resonator to be tuned.

Abstract: A stable resonator for a ring-down cavity spectroscopy cell having an optic axis. The resonator includes two Brewster's angle retroreflector prisms, at least one prism having greater than two total internal reflection surfaces. The prisms are disposed in alignment along the optic axis of the resonator. One or both of the prisms can be rotated so that light rays enter and leave a surface of the prism nearly at Brewster's angle to the normal of the prism surface. This feature maintains alignment between the prisms and allows the resonator to be tuned. One of the total internal reflection surfaces of at least one of the prisms may be a curved surface (either a ground curved surface or a surface curved by the addition, through optically contacting or gluing, of a plano-convex lens to the surface).

Abstract: A stable resonator for a ring-down cavity spectroscopy cell having an optic axis. The resonator includes two Brewster's angle retroreflector prisms, each having a plurality of total internal reflection surfaces. The prisms are disposed in alignment along the optic axis of the resonator. One or both of the prisms can be rotated so that light rays enter and leave a surface of the prism nearly at Brewster's angle to the normal of the prism surface. This feature maintains alignment between the prisms and allows the resonator to be tuned. One of the total internal reflection surfaces of at least one of the prisms may be a curved surface (either a ground curved surface or a surface curved by the addition, through optically contacting or gluing, of a plano-convex lens to the surface). Alternatively, an astigmatic lens may be centered in one arm of the resonator and tilted at Brewster's angle with respect to the optic axis of the resonator. In a preferred embodiment, each of the prisms has an apex angle of about 135.

Abstract: A stable resonator for a ring-down cavity spectroscopy cell having an optic axis. The resonator includes two Brewster's angle retroreflector prisms, each having a plurality of total internal reflection surfaces. The prisms are disposed in alignment along the optic axis of the resonator. One or both of the prisms can be rotated so that light rays enter and leave a surface of the prism nearly at Brewster's angle to the normal of the prism surface. This feature maintains alignment between the prisms and allows the resonator to be tuned. One of the total internal reflection surfaces of at least one of the prisms may be a curved surface (either a ground curved surface or a surface curved by the addition, through optically contacting or gluing, of a plano-convex lens to the surface). Alternatively, an astigmatic lens may be centered in one arm of the resonator and tilted at Brewster's angle with respect to the optic axis of the resonator. In a preferred embodiment, each of the prisms has an apex angle of about 135.

Abstract: The present invention teaches a unique laser radiometer capable of accurately measuring the radiation temperature of a radiant surface and independently measuring the surface's emissivity. A narrow-band radiometer is combined with a laser reflectometer to measure concurrently radiance and emissivity of a remote, hot surface. Together, radiance and emissivity yield the true surface temperature of the remote target. A narrow receiver bandwidth is attained by one of two methods; (a) heterodyne detection or (b) optical filtering. A direct measurement of emissivity is used to adjust the value obtained for the thermal radiation signal to substantially enhance the accuracy of the temperature measurement for a given subject surface. The technique provides substantially high detection sensitivity over a very narrow spectral bandwidth.

Abstract: A device is disclosed for producing a pair of synchronized intense 16 micron pulses in which stimulated rotational Raman scattering together with four wave mixing and pulse compression takes place in parahydrogen on an off-axis path between a pair of spherical mirrors.

Abstract: This application discloses a method of separating the isotopes of an element which form a volatile compound having an isotopically shifted but overlapping infrared absorption spectrum. In the method, IR radiation of first and second laser frequencies are employed. The first infrared laser frequency produces a selective excitation of the desired isotope of the compound, while the second infrared laser frequency produces a higher multiphoton excitation which allows conversion of the excited compound.

Abstract: A device is disclosed for producing intense 16 micron radiation in which stimulated rotational Raman scattering takes place in parahydrogen on an off-axis path between a pair of spherical mirrors.