System and method for chemical sensing using trace gas detection
First Claim
1. A system for detecting a chemical, comprising:
- a strobe configured to irradiate a first beam with a spectral energy band across at least a portion of a characteristic absorption band of a trace gas associated with the chemical;
a probe unit sending and receiving a probe beam, the probe unit configured to interferometrically sense and measure the absorption of the first beam by molecules of the trace gas by mixing the received probe beam with a local oscillator beam, coming from a local oscillator unit, and determine the trace gas concentration;
a look-up table to identify what chemical corresponds to the determined trace gas;
wherein the trace gas is at a remote location from the strobe and the probe unit.
1 Assignment
0 Petitions
Accused Products
Abstract
A system and method is proposed for chemicals detection such as explosives and others, which are based on sensing of trace gases associated with the chemical. This sensing includes detection of spectrum and relative concentration of the trace gases followed by the chemical identification based on these data. The sensing is based on photothermal interferometry method modified by implementation of coherent optical detection. This modification essentially improves the device performance by increasing its sensitivity and selectivity. Improved characteristics of the device allow remote sensing of the interrogated chemicals at a distance up to 1000 meters, which is crucial for explosives detection. The coherent optical detection is performed by a coherent receiver based on 90-degrees optical hybrid.
-
Citations
20 Claims
-
1. A system for detecting a chemical, comprising:
-
a strobe configured to irradiate a first beam with a spectral energy band across at least a portion of a characteristic absorption band of a trace gas associated with the chemical; a probe unit sending and receiving a probe beam, the probe unit configured to interferometrically sense and measure the absorption of the first beam by molecules of the trace gas by mixing the received probe beam with a local oscillator beam, coming from a local oscillator unit, and determine the trace gas concentration; a look-up table to identify what chemical corresponds to the determined trace gas; wherein the trace gas is at a remote location from the strobe and the probe unit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
-
-
20. A method for determining information about a chemical, comprising:
-
directing a first beam to a remote location where a trace gas associated with the chemical is present, the first beam having one or more wavelengths that are in absorption band of a trace gas associated with the chemical, wherein the first beams interacts with the trace gas changing a refractive index of the trace gas; directing a probe beam to interact with the trace gas, receiving at least a portion of the probe beam at a receiver positioned remotely from the trace gas; mixing the received probe beam with a local oscillator beam producing interference and measuring a phase shift of the probe beam that is induced by the first beam and is indicative of at least one of, absorption spectrum and concentration of the trace gas; using a look-up table to identify the chemical basing on determined concentration of the trace gas.
-
Specification