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Gill, MA, United States

Chaudhery V.,University of Illinois at Urbana - Champaign | Lu M.,SRU Biosystems | Huang C.S.,University of Illinois at Urbana - Champaign | George S.,University of Illinois at Urbana - Champaign | Cunningham B.T.,University of Illinois at Urbana - Champaign
Journal of Fluorescence | Year: 2011

The effect of resonant fluorescent enhancement from a photonic crystal surface upon the fluorescent photobleaching rate of Cyanine-5 labeled protein has been investigated. We show that the enhanced excitation mechanism for photonic crystal enhanced fluorescence, in which the device surface resonantly couples light from an excitation laser, accelerates photobleaching in proportion to the coupling efficiency of the laser to the photonic crystal. We also show that the enhanced extraction mechanism, in which the photonic crystal directs emitted photons approximately normal to the surface, does not play a role in the rate of photobleaching. We show that the photobleaching rate of dye molecules on the photonic crystal surface is accelerated by 30x compared to an ordinary glass surface, but substantial signal gain is still evident, even after extended periods of continuous illumination at the resonant condition. © 2010 Springer Science+Business Media, LLC. Source

Ge C.,University of Illinois at Urbana - Champaign | Lu M.,SRU Biosystems | Tan Y.,University of Illinois at Urbana - Champaign | Cunningham B.T.,University of Illinois at Urbana - Champaign
Optics Express | Year: 2011

A 22× reduction in laser pump threshold and a 23× enhancement in energy conversion have been demonstrated on a second order distributed feedback (DFB) laser using a resonant optical pumping (ROP) technique. The ROP scheme couples the excitation light into a distinct resonant mode of the laser cavity through the illuminating at a specific resonant incident angle. Coupling excitation light into the resonant mode results in an enhanced near-field, which significantly increases pump absorption by the active medium. Consequently, high power conversion efficiency between pumping light and lasing emission is achieved and laser pump threshold power is reduced. © 2011 Optical Society of America. Source

Tan Y.,University of Illinois at Urbana - Champaign | Ge C.,University of Illinois at Urbana - Champaign | Chu A.,University of Illinois at Urbana - Champaign | Lu M.,SRU Biosystems | And 5 more authors.
IEEE Sensors Journal | Year: 2012

A process that combines polymer nanoreplica molding with horizontal dipping was used to fabricate large area (∼ 3 × 5 inch 2) distributed feedback laser biosensors (DFBLB) on flexible plastic substrates, which were subsequently incorporated into standard format 96-well microplates. A room temperature nanoreplica molding process was used to create subwavelength periodic grating structures, while a horizontal dipping process was used to apply a ∼ 300 nm, dye-doped polymer film. In this work, the DFBLB emission wavelength, used to characterize the device uniformity, demonstrated a coefficient of variation (CV) of 0.41% over the fabricated device area, representing a thickness standard deviation of only ∼ 35 nm for the horizontal dipping process. The fabricated sensors were further characterized for sensitivity uniformity by measuring the bulk refractive index of the media exposed to the sensor surface and by measuring adsorption of biomolecular layers. An assay for detection of the cytokine Tumor Necrosis Factor-alpha (TNF-α) was used to demonstrate the operation of the sensor in the context of label-free detection of a disease biomarker. The demonstrated capability represents an important step towards roll-to-roll manufacturability for this biosensor that simultaneously incorporates high sensitivity with excellent wavelength shift resolution, and adaptability to the microplate format that is ubiquitous in pharmaceutical research. © 2011 IEEE. Source

Zheng J.,Urbana University | Ge C.,Urbana University | Wagner C.J.,Urbana University | Lu M.,SRU Biosystems | And 3 more authors.
Optics Express | Year: 2012

Continuous tuning over a 1.6 THz region in the near-infrared (842.5-848.6 nm) has been achieved with a hybrid ring/external cavity laser having a single, optically-driven grating reflector and gain provided by an injection-seeded semiconductor amplifier. Driven at 532 nm and incorporating a photonic crystal with an azobenzene overlayer, the reflector has a peak reflectivity of ̃80% and tunes at the rate of 0.024 nm per mW of incident green power. In a departure from conventional ring or external cavity lasers, the frequency selectivity for this system is provided by the passband of the tunable photonic crystal reflector and line narrowing in a high gain amplifier. Sub - 0.1 nm linewidths and amplifier extraction efficiencies above 97% are observed with the reflector tuned to 842.5 nm. © 2012 Optical Society of America. Source

Ge C.,University of Illinois at Urbana - Champaign | Lu M.,SRU Biosystems | Jian X.,University of Illinois at Urbana - Champaign | Tan Y.,University of Illinois at Urbana - Champaign | Cunningham B.T.,University of Illinois at Urbana - Champaign
Optics Express | Year: 2010

The fabrication of visible wavelength vertically emitting distributed feedback (DFB) lasers with a subwavelength grating fabricated by a replica molding process and an active polymer layer printed by a horizontal dipping process is reported. The combined techniques enable the organic DFB laser to be uniformly fabricated over large surface areas upon a flexible plastic substrate, with an approach that is compatible with rollbased manufacturing. Using a fixed grating period and depth, DFB laser output wavelength is controlled over a 35 nm range through manipulation of the waveguide layer thickness, which is controlled by the speed of the horizontal dipping process. We also demonstrate that the active area of the structure may be photolithographically patterned to create dense arrays of discrete DFB lasers. © 2010 Optical Society of America. Source

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