Combining a DS-DBR laser with QPM-DFG for mid-infrared spectroscopy
- 313 Downloads
Studies into the suitability of a novel, widely tunable telecom L-band (1563–1613 nm) digital supermode distributed Bragg reflector (DS-DBR) laser for spectroscopy in the mid-IR are presented. Light from the DS-DBR laser was mixed with 1064 nm radiation in a periodically poled lithium niobate (PPLN) crystal to generate mid-IR light by quasi phase matching difference frequency generation (QPM-DFG). The resultant continuous wave radiation covered the range 3000–3200 cm−1 with powers of up to 2.6 μW. The use of such laser light for spectroscopic applications was illustrated by performing absorption experiments on both narrow-band and broad-band absorbers, namely methane (CH4) and methanethiol (CH3SH). Wavelength modulation spectroscopy (WMS) on CH4 demonstrated that the modulation characteristics of the DS-DBR laser observed in the near-IR were transposed to the mid-IR and yielded a sensitivity of 3.1×10−6 cm−1 Hz−1/2 over a 47 cm path length. In the CH3SH spectrum, the absorption feature at 3040 cm−1 was identified as a potential useful region for monitoring this biomarker in exhaled breath at reduced pressures.
KeywordsFull Width Half Maximum Periodically Pole Lithium Niobate Difference Frequency Generation Quasi Phase Match Wavelength Modulation Spectroscopy
The authors would like to thank Andrew Orr-Ewing from the University of Bristol for the use of the L-band EDFA required to perform these measurements and to Bookham Technology for the DS-DBR laser. The authors are also grateful to the EPSRC for providing a Doctoral Training Award for this project (KEW), an advanced research fellowship (RP) and financial support through the grant EP/E019765/1.
- 2.F.K. Tittel, D. Richter, A. Fried, in Topics in Applied Physics, ed. by I.T. Sorokina, K.L. Vodopyanov. Solid-State Mid-Infrared Laser Sources, vol. 89 (Springer, Berlin, 2003), pp. 445–510 Google Scholar
- 8.R.W. Boyd, Nonlinear Optics (Academic Press, San Diego, 2003) Google Scholar
- 9.Lockheed Martin Aculight, Bothell, USA (2012), http://www.lockheedmartin.com/us/products/aculight.html
- 24.L.S. Rothman, D. Jacquemart, A. Barbe, D. Chris Benner, M. Birk, L.R. Brown, M.R. Carleer, C. Chackerian Jr., K. Chancea, L.H. Coudert, V. Dana, V.M. Devi, J.-M. Flaud, R.R. Gamache, A. Goldman, J.-M. Hartmann, K.W. Jucks, A.G. Maki, J.-Y. Mandin, S.T. Massie, J. Orphal, A. Perrin, C.P. Rinsland, M.A.H. Smith, J. Tennyson, R.N. Tolchenov, R.A. Toth, J. Vander Auwera, P. Varanasi, G. Wagner, J. Quant. Spectrosc. Radiat. Transf. 96, 139 (2005) ADSCrossRefGoogle Scholar
- 25.L.R. Brown, D. Chris Benner, J.P. Champion, V.M. Devi, L. Fejard, R.R. Gamache, T. Gabard, J.C. Hilico, B. Lavorel, M. Loete, G.Ch. Mellau, A. Nikitin, A.S. Pine, A. Predoi-Cross, C.P. Rinsland, O. Robert, R.L. Sams, M.A.H. Smith, S.A. Tashkun, Vl.G. Tyuterev, J. Quant. Spectrosc. Radiat. Transf. 82, 219 (2003) ADSCrossRefGoogle Scholar
- 30.Pacific Northwest National Laboratory, Vapor Phase Infrared Spectral Library (2012), http://nwir.pnl.gov