title: Optofluidic FRET lasers using aqueous quantum dots as donors.
abstract: An optofluidic FRET (fluorescence resonance energy transfer) laser is formed by putting FRET pairs inside a microcavity acting as a gain medium. This integration of an optofluidic laser and the FRET mechanism provides novel research frontiers, including sensitive biochemical analysis and novel photonic devices, such as on-chip coherent light sources and bio-tunable lasers. Here, we investigated an optofluidic FRET laser using quantum dots (QDs) as FRET donors. We achieved lasing from Cy5 as the acceptor in a QD-Cy5 pair upon excitation at 450 nm, where Cy5 has negligible absorption by itself. The threshold was approximately 14 μJ mm(-2). The demonstrated capability of QDs as donors in the FRET laser greatly improves the versatility of optofluidic laser operation due to the broad and large absorption cross section of the QDs in the blue and UV spectral regions. The excitation efficiency of the acceptor molecules through a FRET channel was also analyzed, showing that the energy transfer rate and the non-radiative Auger recombination rate of QDs play a significant role in FRET laser performance.
authors.affiliation: Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA. akiraz@ku.edu.tr xsfan@umich.edu.
authors.forename: Qiushu
authors.initials: Q
authors.lastname: Chen
authors.affiliation: Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA. akiraz@ku.edu.tr xsfan@umich.edu and Department of Physics, Koç University, Rumelifeneri Yolu, Sariyer, 34450 Istanbul, Turkey.
authors.forename: Alper
authors.initials: A
authors.lastname: Kiraz
authors.affiliation: Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA. akiraz@ku.edu.tr xsfan@umich.edu.
authors.forename: Xudong
authors.initials: X
authors.lastname: Fan
mesh_terms: D002232:Carbocyanines / Q000737:chemistry*; D031541:Fluorescence Resonance Energy Transfer; D007834:Lasers; D055096:Optical Devices; D045663:Quantum Dots; D014867:Water / Q000737:chemistry
chemical_list: D002232:Carbocyanines; C085321:cyanine dye 5; D014867:Water