Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7932575 | Optics Communications | 2013 | 6 Pages |
Abstract
Standoff Quartz Enhanced Laser Photoacoustic Spectroscopy (QE-LPAS) technique is emerging as a powerful technique for detection of hazardous chemicals, biological and explosive agents. Experimentally, we have recorded standoff photoacoustic spectrum of hazardous molecules adsorbed at diffused surfaces from a distance of up to 25 m. Tunable mid infrared quantum cascade lasers (MIR-QCL) in the wavelength range 7.0-12.0 μm are being used as optical source. Samples of Dinitrotoluene (DNT), Pentaerythritoltetranitrate (PETN) having adsorbed concentration of approximately 5.0 μg/cm2 were detected. Acetone and nitrobenzene samples in liquid having concentration 200 nl approximately sealed in polythene sachet were detected from a standoff distance of up to 25 m. All the above measurements are reported for a Signal to Noise Ratio (SNR) of 10, optimized for maintaining very less false alarm rates for field measurements. A portable trolley mounted system has been developed for field applications.
Related Topics
Physical Sciences and Engineering
Materials Science
Electronic, Optical and Magnetic Materials
Authors
Ramesh C. Sharma, Deepak Kumar, Neha Bhardwaj, Saurabh Gupta, Hukum Chandra, Anil K. Maini,