Browse Prior Art Database

TECHNIQUE FOR PORTABLE RAMAN CHEMICAL / BIOLOGICAL DETECTION

IP.com Disclosure Number: IPCOM000198545D
Publication Date: 2010-Aug-09
Document File: 5 page(s) / 213K

Publishing Venue

The IP.com Prior Art Database

Abstract

A technique for the detection of chemical and biological substances is disclosed. This technique detects the chemical and biological substances using Raman spectroscopy. The Raman system uses a modulated 405 nm and 785 nm lasers for near resonance and normal Raman operation. The proposed technique eliminates interference from sample or environmental luminescence and further eliminates need for high cost picoseconds pulsed laser. The proposed technique efficiently rejects phosphorescence, fluorescence, and ambient light that inhibit sample identification using the Raman system.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 59% of the total text.

Page 1 of 5

RP13472

TECHNIQUE FOR PORTABLE RAMAN CHEMICAL / BIOLOGICAL DETECTION

BRIEF ABSTRACT

    A technique for the detection of chemical and biological substances is disclosed. This technique detects the chemical and biological substances using Raman spectroscopy. The Raman system uses a modulated 405 nm and 785 nm lasers for near resonance and normal Raman operation. The proposed technique eliminates interference from sample or environmental luminescence and further eliminates need for high cost picoseconds pulsed laser. The proposed technique efficiently rejects phosphorescence, fluorescence, and ambient light that inhibit sample identification using the Raman system.

KEYWORDS

    Raman spectroscopy, field analysis, fluorescence interference, Phosphorescence, Light chemical detection, biological detection, explosives detection

DETAILED DESCRIPTION

    Recent advances in portable Raman instruments have dramatically increased their application to emergency response, detection, forensics, homeland defense among others. Spontaneous Raman spectroscopy has moderate selectivity and poor sensitivity. Detection has been demonstrated at 50 meters and 500 meters on some solvents and polymeric materials. The use

1

Page 2 of 5

RP13472

of Resonance Raman spectroscopy provides improvement in sensitivity and selectivity compared to the spontaneous Raman spectroscopy.

    Various spectroscopy techniques are used to detect harmful substances. Detection of the harmful substances is due to spectroscopy's capacity for high selectivity and sensitivity. Vibrational spectroscopy is capable of unique identification of molecular substances. This capability exists because of each molecule's unique vibrational frequencies depend on molecular structure, such as bond length, bond strength, mass and coupling of the molecular motion to light.

    Conventional systems, such as jet-REMPI (Resonant Enhanced Multi Photon Ionization) are used for the detection of various substances. However, the REMPI system is unable to ionize the molecule by using one laser and therefore two lasers with different wavelength must be used.

    Therefore there is a need in the art to develop an efficient system for biological and chemical detection using Raman spectroscopy.

    Figure 1 is a block diagram of a phase resolved Raman spectrometer. The modulation...