Lab-in-a-tube: on-chip integration of glass optofluidic ring resonators for label-free sensing applications.
ABSTRACT The fabrication of tubular rolled-up optofluidic ring resonators (RU-OFRRs) based on glass (SiO(2)) material with high quality factors is reported. A novel methodology combining lab-on-a-chip fabrication methods and rolled-up nanotech is presented for the fabrication of fully integrated tubular optofluidic sensors. The microfluidic integration of several RU-OFRRs on one chip is solved by enclosing the microtubes with a patterned robust SU-8 polymeric matrix. A viewport on each microtube enables exact excitation and monitoring of whispering gallery modes with a photoluminescence spectroscopy system under constant ambient conditions, while exchanging the content of the RU-OFRR with liquids of different refractive indices. The refractrometric sensor capabilities are investigated regarding signal stability, sensitivity and reliability. The sensitivity of the integrated RU-OFRR, which is the response of the modes to the change in refractive index of the liquid, is up to 880 nm/refractive index units (RIU).
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ABSTRACT: Advances in microanalytical systems for multi-vapor determinations to date have been impeded by limitations associated with the microsensor technologies employed. Here we introduce a microfabricated optofluidic ring resonator (μOFRR) sensor that addresses many of these limitations. The μOFRR combines vapor sensing and fluidic transport functions in a monolithic microstructure comprising a hollow, vertical SiOx cylinder (250 μm i.d., 1.2 μm wall thickness; 85 μm height) with a central quasi-toroidal mode-confinement section, grown and partially released from a Si substrate. The device also integrates on-chip fluidic-interconnection and fiber-optic probe alignment features. High-Q whispering gallery modes generated with a tunable 1550 nm laser exhibit rapid, reversible shifts in resonant wavelength arising from polymer swelling and refractive index changes as vapors partition into the ~300 nm PDMS film lining the cylinder. Steady-state sensor responses varied in proportion to concentration over a 50-fold range for the five organic vapors tested, providing calculated detection limits as low as 0.5 ppm (v/v) (for m-xylene and ethylbenzene). In dynamic exposure tests, responses to 5 μL injected m-xylene vapor pulses were 710 ms wide and were only 18% broader than those from a reference flame-ionization detector and also varied linearly with injected mass; 180 pg was measured and the calculated detection limit was 49 pg without use of preconcentration or split injection, at a flow rate compatible with efficient chromatographic separations. Coupling of this μOFRR with a micromachined gas chromatographic separation column is demonstrated.Lab on a Chip 08/2014; 14(19). DOI:10.1039/c4lc00739e · 5.75 Impact Factor
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ABSTRACT: Crystalline semiconductor nanomembranes (NMs) offer unprecedented opportunities for unique electronic and photonic devices for vertically stacked high-density photonic/electronic integration, high-performance flexible electronics, and adaptive flexible/conformal photonics. We present here major progresses reported over the last year, in the area of semiconductor NM photonics, with focuses on the innovative membrane laser devices and structures for silicon photonics and flexible optoelectronics.IEEE Photonics Journal 04/2013; 5(2):0700707-0700707. DOI:10.1109/JPHOT.2013.2250942 · 2.33 Impact Factor
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ABSTRACT: A significant step towards integrated vertically rolled-up microcavities is demonstrated by interfacing an as-fabricated SiO2 microtube optical ring resonator with tapered fibers. In this transmission configuration, resonant filtering of optical signals at telecommunication wavelengths is shown in subwavelength thick walled microcavities. Moreover, we present a four-port add-drop filter based on a lifted doubly interfaced vertically rolled-up microcavity. Our work opens opportunities for vertical resonant light transfer in 3D multi-level optical data processing as well as for massively parallel optofluidic analysis of biomaterials in lab-on-a-chip systems.Applied Physics Letters 06/2013; 102:251119. DOI:10.1063/1.4812661 · 3.52 Impact Factor