System for remote chemical analysis

Claim 2

An improved system for remote chemical analysis wherein a sample species is disposed in a location remote from the means whereby the analysis is effected comprising: a sample cell means adapted to receive therein or convey therethrough a species of interest to be analyzed which species has predetermined infrared absorption characteristics, said sample cell means having window means on opposed sides thereof for the passage of light therethrough; an infrared light source; an acousto-optic tunable filter analyzer system, which system comprises an acousto-optic tunable filter having an optically aligned acousto-optic crystal through which the infrared radiation is passed at a predetermined angle relative to the crystal optic axis, an acoustic transducer means coupled to a variable frequency rf energy source and to the acousto-optic crystal to launch acoustic waves into the crystal to interact with a selected narrow bandwidth portion of the infrared radiation to make it distinguishable from the remaining infrared radiation, which selected narrow bandwidth portion is a function of the frequency of the rf energy and acoustic waves; means for focusing light from said infrared light sorce onto said acousto-optic tunable filter at the predetermined angle; at least a first optical fiber which transmits the selected narrow bandwidth portion from the acousto-optic crystal to said sample cell; a second optical fiber disposed between said sample cell means and an infrared radiation detection means; said infrared radiation detection means generating an output signal as a function of the output filter infrared radiation having passed through said sample cell means; computing means to which the detection means output signal is applied for determining the species present in said sample cell means and including means for the pulsed operation of the rf energy source to determine timing and frequency of rf energy applied to the acoustic transducer made into the acousto-optic crystal to determine the infrared wavelength selectivity for tuning of the acousto-optic tunable filter.

Claim 3

The improved system for remote chemical analysis according to claim 1 wherein the acousto-optic tunable filter is a thallium arsenic selenide crystal.

Claim 4

The improved system for remote chemical analysis according to claim 1 wherein the acousto-optic tunable filter includes polarizers disposed on the input and output sides of the crystal.

Claim 5

An improved system for remote chemical analysis wherein a sample species is disposed in a location remote from the means whereby the analysis is effected comprising: a sample cell means adapted to receive therein or convey therethrough a species of interest to be analyzed which species has predetermined infrared absorption characteristics, said sample cell means having window means on opposed sides thereof for the passage of light therethrough; an infrared light source; a first optical fiber; means for focusing light from said infrared light source into said first optical fiber which is in communication with said sample cell means; a second optical fiber disposed between said sample cell means and an acousto-optic dispersive light filter (AODLF) analyzer system; means for focusing the infrared radiation after modification by the absorption characteristic of the sample species onto said second optical fiber for the transmission of the so-modified infrared radiation to said AODLF analyzer system; and said AODLF analyzer system including an optically birefrigent crystal having an optical input face, and optical output face said optical input face being disposed a predetermined angle which is normal to the incident light, means acoustically coupled with one of said sides for launching acoustic waves into said crystal at a predetermined fixed frequency wherein each wavelength resolution element which emerges from the optical output face is at a different diffracted angle, and wherein the predetermined angle of the optical input face is selected such that for the fixed acoustic frequency, there is a minimum in the Bragg angle with frequency, while the diffracted Bragg angle increases linearly with frequency, an acoustic transducer means coupled to a variable frequency rf energy source and to the crystal to launch acoustic waves into the crystal; an infrared radiation detector array which detects the output infrared radiation from the acousto-optic dispersive light filter and generates an output signal as a function of the output filtered infrared radiation; and computing means to which the detection means output signal is applied for determining the species present in the sample cell and including means for the pulse operation of the rf energy source to determine timing and frequency of rf energy applied to the acoustic transducer mated to the acousto-optic crystal to determine the infrared wavelength selectivity for tuning of the acousto-optic tunable filter.

Claim 6

An improved system for remote chemical analysis wherein a sample species is disposed in a location remote from the means whereby the analysis is effected comprising: a sample cell means adapted to receive therein or convey therethrough a species of interest to be analyzed which species has predetermined infrared absorption characteristics, said sample cell means having window means on opposed sides thereof for the passage of light therethrough; an infrared light source; a first optical fiber; means for focusing light from said infrared light source into said first optical fiber which is in communication with said sample cell means; a second optical fiber disposed between said sample cell means and an acousto-optic dispersive light filter (AODLF) analyzer system; means for focusing the infrared radiation after modification by the absorption characteristic of the sample species onto said second optical fiber for the transmission of the so-modified infrared radiation to said AODLF analyzer system; and said AODLF analyzer system including an optically birefrigent crystal having an optical input face, and optical output face said optical input face being disposed a predetermined angle which is normal to the incident light, means acoustically coupled with one of said sides for launching acoustic waves into said crystal at a predetermined fixed frequency wherein each wavelength resolution element which emerges from the optical output face is at a different diffracted angle, and wherein the predetermined angle of the optical input face is selected such that for the fixed acoustic frequency, there is a minimum in the Bragg angle with frequency, while the diffracted Bragg angle increases linearly with frequency, an acoustic transducer means coupled to a variable frequency rf energy source and to the crystal to launch acoustic waves into the crystal; an infrared radiation detector array which detects the output infrared radiation from the acousto-optic dispersive light filter and generates an output signal as a function of the output filtered infrared radiation; and computing means to which the detection means output signal is applied for determining the species present in the sample cell and including means for the pulse operation of the rf energy source to determine timing and frequency of rf energy applied to the acoustic transducer mated to the acousto-optic crystal to determine the infrared wavelength selectivity for tuning of the acousto-optic tunable filter.

Claim 7

The improved system for remote chemical analysis according to claim 4 wherein the acousto-optic tunable filter is a thallium arsenic selenide crystal.

Claim 8

The improved system for remote chemical analysis according to claim 4 wherein the acousto-optic tunable filter includes polarizers disposed on the input and output sides of the crystal.

Claim 9

An acousto-optic device for spectral analysis use in a fiber optic system comprising: a housing defining an enclosure in which is mounted an acousto-optic device having an optically aligned acousto-optic crystal through which radiation is passed at a predetermined angle relative to the crystal optic axis, an acoustic transducer means coupled to the acousto-optic crystal to launch acoustic waves into the crystal to interact with a selected narrow bandwidth portion of the radiation to make it distinguishable from the remaining radiation, which selected narrow bandwidth portion is a function of the frequency of an RF energy drive in communication with said transducer means; optical fiber input connector means disposed on a side of said housing proximate the input face of the acousto-optic crystal and adapted to removably receive thereon an optic fiber; optical fiber connector output means disposed in said housing approximate the output face of said crystal and adapted for interconnection with an optical fiber; and RF connector means disposed on said housing and in electrical communication with said acoustic transducer means of said acousto-optic crystal and adapted to be coupled to an RF energy source.

Claim 10

An acousto-optic device for spectral analysis use in a fiber optic system comprising: a housing defining an enclosure in which is mounted an acousto-optic device having an optically aligned acousto-optic crystal through which radiation is passed at a predetermined angle relative to the crystal optic axis, an acoustic transducer means coupled to the acousto-optic crystal to launch acoustic waves into the crystal to interact with a selected narrow bandwidth portion of the radiation to make it distinguishable from the remaining radiation, which selected narrow bandwidth portion is a function of the frequency of an RF energy drive in communication with said transducer means; optical fiber input connector means disposed on a side of said housing proximate the input face of the acousto-optic crystal and adapted to removably receive thereon an optic fiber; optical fiber connector output means disposed in said housing approximate the output face of said crystal and adapted for interconnection with an optical fiber; and RF connector means disposed on said housing and in electrical communication with said acoustic transducer means of said acousto-optic crystal and adapted to be coupled to an RF energy source.

Claim 11

The acousto-optic device according to claim 7 including lens means disposed in said housing between the input connector and the input face of the acousto-optic crystal.

Claim 12

The acousto-optic device according to claim 8 including lens means disposed in said housing between the output face of the crystal and the output optical connector means.

Claim 13

The acousto-optic device according to claim 7 including lens means disposed in said housing between the output face of the crystal and the output optical connector means.