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Title: Raman signal enhancement by multiple beam excitation and its application for the detection of chemicals

Journal Article · · Applied Physics Letters
DOI:https://doi.org/10.1063/1.4929951· OSTI ID:22489190
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  1. Laser Science and Technology Centre, Metcalfe House, Delhi 110054 (India)

In a typical Raman based sensor, a single laser beam is used for exciting the sample and the backscattered or forward scattered light is collected using collection optics and is analyzed by a spectrometer. We have investigated that by means of exciting the sample with multiple beams, i.e., by dividing the same input power of the single beam into two or three or more beams and exciting the sample from different angles, the Raman signal enhances significantly. Due to the presence of multiple beams passing through the same volume of the sample, an interference pattern is formed and the volume of interaction of excitation beams with the sample increases. By means of this geometry, the enhancement in the Raman signal is observed and it was found that the signal strength increases linearly with the increase in number of excitation beams. Experimental results of this scheme for excitation of the samples are reported for explosive detection at a standoff distance.

OSTI ID:
22489190
Journal Information:
Applied Physics Letters, Vol. 107, Issue 9; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
Country of Publication:
United States
Language:
English