Patents
US 8395777 B2: Method and apparatus for trace gas detection using integrated wavelength modulated spectra across multiple lines
- Granted
- 2013-03-12
- Filed
- 2011-02-11 application 13025991
- Type
- Utility · 28 claims
- Elsewhere
- Google Patents ↗ · USPTO patent document ↗ · USPTO Patent Center record ↗
Abstract
An apparatus and technique are invented that enhance the sensitivity of a spectrometer for trace gas detection by employing wavelength modulation spectroscopy (WMS) and integrating the absolute value of the recorded spectra across multiple absorption lines (features) of the species. The sensitivity is further enhanced by conducting WMS with large modulation depths. This technique is implemented using a continuously tunable external cavity CW quantum cascade laser to record the second harmonic wavelength modulated spectra of NO2 across the peak of the R-branch from 1629.5 cm−1 to 1633.9 cm−1. By integrating the absolute value of the resulting spectra, the detection sensitivity of NO2 is improved by a factor of 40 compared to the sensitivity achieved using single line WMS with the same apparatus. A sensitivity of approximately 6 ppb can be obtained using a short-path cell (a 1 m absorption cell with 2 passes) which can be significantly improved using multipass cells and cavity enhanced techniques.
Source: PVGPATDIS, file of 2026-04-10 (ipg130312.xml).
Assignees
| Assignee | Type | Place | Also on furp.org | Source |
|---|---|---|---|---|
| Adelphi University 4 patents | US company or organization | Garden City, NY | Adelphi University College or university EXACT high confidence: identical full name and state ADELPHI UNIVERSITY Nonprofit EXACT high confidence: identical full name and state | PVGPATDIS, file of 2026-04-10 |
Inventors
| Inventor | Place | Patents | Person page | Source |
|---|---|---|---|---|
| Gottipaty Rao | West Hempstead, NY | 3 | PVGPATDIS, file of 2026-04-10 |
CPC categories
| Subclass | Category | First group | Source |
|---|---|---|---|
| G01J | Measurement of intensity, velocity, spectral content, polarisation, phase or pulse characteristics of infrared, visible or ultraviolet light; colorimetry; radiation pyrometry | G01J3/4338 | PVGPATDIS, file of 2026-04-10 |
| G01N | Investigating or analysing materials by determining their chemical or physical properties | G01N21/39 | PVGPATDIS, file of 2026-04-10 |
Cooperative Patent Classification, as currently assigned (one row per subclass).
Assignments and security interests
| Recorded | What | From | To | Reel/frame | Source |
|---|---|---|---|---|---|
| 2011-02-14 | Assignment Assignment of assignor's interest | RAO, GOTTIPATY signed 2011-02-10 | ADELPHI UNIVERSITY GARDEN CITY, NY | 25802/592 | ECORSEXC, file of 2026-09-25 |
Documents recorded with the USPTO Assignment Recordation Branch that list this patent. A security interest is a lender’s claim on the patent as collateral; a release ends it.
USPTO bulk data: PatentsView granted patents, disambiguated (PVGPATDIS) for patents, assignees, inventors, places and CPC categories; the USPTO Patent Assignment Dataset (ECORSEXC) for assignments and security interests. Patents filed in the last 20 years. No claims or full text. Links to other records are by name (and state): EXACT means the identical full name and state; FUZZY means a looser name match, with the confidence shown.