MID-IR ETHENE DETECTION USING A QUASI-PHASE MATCHED LiNbO$_3$ WAVEGUIDE
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Date
2009
Journal Title
Journal ISSN
Volume Title
Publisher
Ohio State University
Abstract
A periodically poled LiNbO$_3$ waveguide has been used to produce up to 200 $\mu$W of mid-infrared light around 3081 cm$^{-1}$ with a wide tunability range of $>$33 cm$^{-1}$. Two commercial near-infrared diode lasers at 1.064 $\mu$m (pump) and 1.583 $\mu$m (signal) are mixed in a nonlinear optical crystal to achieve difference frequency generation. The 48 mm long direct-bonded quasi-phase matched periodically poled LiNbO$_{3}$ waveguide shows a conversion efficiency of 12.3 \%/W. The radiation sits in an important window of the mid-infrared spectral region, where a large number of fundamental vibrations of several hydrocarbons occur. Applications in trace gas detection have been demonstrated for ethene, using multi-pass absorption coupled with wavelength modulation spectroscopy to reach a minimum absorption coefficient of 3 $\times$ 10$^{-7}$ cm$^{-1}$ Hz$^{-1/2}$. The relatively high power of the mid-infrared idler radiation obtained shows great potential for higher sensitive techniques such as cavity enhanced absorption spectroscopy and cavity ring-down spectroscopy, and preliminary results will be presented. \underline{\textbf{94}}, 517-525, 2009.}
Description
L.~Ciaffoni, R.~Grilli, G.~Hancock, A.J.~Orr-Ewing, R.~Peverall and G.~A.~D.~Ritchie \textit{Appl.~Phys.~B
Author Institution: School of Chemistry, University of Bristol, Bristol BS8 1TS, U.K.; Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, U.K.; School of Chemistry, University of Bristol, Bristol BS8 1TS, U.K.
Author Institution: School of Chemistry, University of Bristol, Bristol BS8 1TS, U.K.; Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, U.K.; School of Chemistry, University of Bristol, Bristol BS8 1TS, U.K.