Optofluidic distributed feedback lasers with evanescent pumping : reduced threshold and angular dispersion analysis
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We demonstrate an evanescently pumped water-based optofluidic DFB laser with a record low pump threshold of ETH = 520 nJ. The low threshold results from an optimized mode shape, which is achieved by a low refractive index substrate, and from the use of a mixed-order DFB grating. Investigating the photonic band structure via angular dispersion analysis both above and below lasing threshold allows us to measure the refractive index of the liquid gain layer and to determine device parameters such as the waveguide core layer thickness. We show that it is possible to tailor the divergence of the lasing emission by varying the number of second order grating periods used for outcoupling.
Karl , M , Whitworth , G L , Schubert , M , Dietrich , C P , Samuel , I D W , Turnbull , G A & Gather , M C 2016 , ' Optofluidic distributed feedback lasers with evanescent pumping : reduced threshold and angular dispersion analysis ' Applied Physics Letters , vol 108 , no. 26 , 261101 . DOI: 10.1063/1.4954650
Applied Physics Letters
Copyright 2016 Authors. All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
The authors acknowledge financial support from the European Research Council (ERC StG ABLASE, 640012), the Scottish Funding Council (via SUPA) and the European Union Marie Curie Career Integration Grant (PCIG12-GA-2012-334407). M.K. and G.L.W. acknowledge funding from the EPSRC DTG (EP/M506631/1 and EP/K503162/1). M.S. acknowledges funding from the European Commission for a Marie Sklodowska-Curie Individual Fellowship (659213). I.D.W.S. acknowledges funding from a Royal Society Wolfson research merit award. The research data supporting this publication can be accessed at http://dx.doi.org/10.17630/0ed7dad7-75e1-4ab9-9845-c455d1a7c6a4.