| 11. |
- Junique, Stephane, et al.
(författare)
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A Modulating retro-reflector for free-space optical communication
- 2006
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Ingår i: IEEE Photonics Technology Letters. - 1041-1135 .- 1941-0174. ; 18:1, s. 85-87
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Tidskriftsartikel (refereegranskat)abstract
- We present modeling of a modulating retro-reflector for free-space optical communication, composed of a reflective resonant-cavity modulator and a corner cube. Although resonant-cavity modulators are sensitive to the angle of incidence of the light beam, we show that with the right geometrical arrangement, the field of view can be more than ten-fold that of the modulator. The modeling is validated by experimental data using a corner cube and a 14 x 14 mm(2) multiple quantum-well modulator.
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| 12. |
- Junique, Stephan, et al.
(författare)
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GaAs-based multiple-quantum-well spatial light modulators fabricated by a wafer-scale process
- 2005
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Ingår i: Applied Optics. - 1559-128X .- 2155-3165. ; 44:9, s. 1635-1641
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Tidskriftsartikel (refereegranskat)abstract
- The design, fabrication, and characterization of large, two-dimensional multiple-quantum-well modulator arrays are presented. Such arrays present a speed advantage compared with competing technologies such as liquid crystals and micromirrors, which are intrinsically limited to the kilohertz range. We discuss the design compromises to reach high-contrast, low-voltage swing optical structures compatible with complementary metal-oxide semiconductor-based integrated circuits and present experimental results. Contrast ratio of 5:1 (limited by the fill factor), variations in uniformity below 1 nm, and frame rates in excess of 10 kHz are demonstrated. Technology maturity for volume production is also discussed.
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| 13. |
- Junique, Stephane, et al.
(författare)
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Large–area, three–state, binary amplitude and binary phase vertical–cavity multiple quantum well electroabsorption modulator
- 2007
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Ingår i: Optics Express. - 1094-4087. ; 15:14, s. 8566-8575
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Tidskriftsartikel (refereegranskat)abstract
- We present the design and characterization of a large optical modulator array based on GaAs multiple quantum wells for amplitude and phase modulation. The device shows two high-reflectance states with a phase difference close to 180 degrees for use as a binary phase modulator. It also shows a third, low-reflectance state for use as an amplitude modulator. It is segmented into 64 pixels in a single row, giving an active area of 2mm x 5mm. We discuss the device performance as a ternary binary amplitude and binary phase modulator, including contrast ratio and uniformity, and show that a voltage swing of only 5V is needed to drive it.
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| 14. |
- Li, Xiaohui, et al.
(författare)
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Sensitive label-free and compact biosensor based on concentric silicon-on-insulator microring resonators
- 2009
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Ingår i: Applied Optics. - 1559-128X .- 2155-3165. ; 48:25, s. F90-F94
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Tidskriftsartikel (refereegranskat)abstract
- We propose an ultracompact parallel label-free biosensor based on concentric silicon-on-insulator microring resonators. Our numerical studies show that the proposed biosensor offers higher sensitivity and a larger detection area than conventional single-ring-based sensors. We analyze the detection sensitivity of the DNA hybridization by immobilizing the probe on top of the double concentric ring resonators and in the ring-ring air gap. For a concentric double-ring system with an area of 27: 646 mu m(2), the bulk detection sensitivity is 683 nm RIU-1. The sensitive uniformity of the system related to the optical field distribution is also studied.
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| 15. |
- Lv, Yong-Qin, et al.
(författare)
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One-step rapid determination and purification of puerarin from Radix puerariae by n-octylamine-modified poly(methacrylate-co-ethylene dimethacrylate) monolith
- 2008
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Ingår i: Journal of chromatography. B. - : Elsevier BV. - 1570-0232 .- 1873-376X. ; 871:1, s. 1-6
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Tidskriftsartikel (refereegranskat)abstract
- n-Octylamine-modified poly(methacrylate-co-ethylene dimethacrylate) monoliths were prepared for rapid screening, determination and one-step purification of puerarin from Radix puerariae (a crude extract of the root of Pueraria lobata). The modified monolith showed a specific surface area of 17.8 m(2) g(-1) an average pore size of 0.76 mu m and a total porosity of 60.8%. Fast separation of R. puerariae crude extract was achieved within 5 min at a flow velocity of 722 cm h(-1) resulting in a puerarin Purity of 97%, with a recovery of 85%. This demonstrates the potential of n-octylamine-modified poly(methacrylate-co-ethylene dimethacrylate) monolith for the rapid analysis and separation of isoflavonoids. Preparative scale sample loading (12 mg in 2 mL) resulted in a purity of 95%, and a recovery of about 69%. HPLC, FTIR, MS and H-1 NMR spectroscopy were used for the characterization and quantification of puerarin in isolated fraction.
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| 16. |
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| 17. |
- Qinlu, Lin, et al.
(författare)
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Influence of amphiphilic structures on the stability of polyphenols with different hydrophobicity
- 2007
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Ingår i: Science in China. Series B: Chemistry. - : Springer Science and Business Media LLC. - 1006-9291 .- 1862-2771. ; 50:1, s. 121-126
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Tidskriftsartikel (refereegranskat)abstract
- Autooxidation of five polyphenols representing range of different hydrophobicities (catechin gallate (CG), (-) catechin((-)C), epicatechin (EC), epigallocatechin gallate (EGCG) and epigallocatechin (EGC)) in three different aqueous solutions: molecular solution, micellar solution (Tween-20) and liposomal dispersion (soybean lecithin) was monitored by HPLC. The rate of oxidation of the five polyphenols was higher at pH 4.5 than at pH 3.5. Compared with the control, addition of Tween-20 (micellar structure) and lecithin (liposomal structure) significantly decreased the degradation of polyphenols. In the presence of lecithin the autooxidation of all the five polyphenols was slower than in the presence of Tween-20. The effective protection of the colloidal structures was compared with the hydrophobicity of the polyphenols estimated from the partitioning between octanol and water. The protection from oxidation in the presence of the colloidal structures (micellar or liposomal) increased with increasing partitioning of a polyphenol towards the hydrophobic environment. The protecting effect of the colloidal structures was more effective at pH 4.5 than at pH 3.5.
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| 18. |
- Sauge, Sebastien, et al.
(författare)
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Quantum communication in optical networks : an overview and selected recent results
- 2007
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Ingår i: ICTON 2007. - 9781424412488 ; , s. 30-33
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Konferensbidrag (refereegranskat)abstract
- We discuss recent work in quantum communication, and in some details present a bright, narrowband, portable, quasi-phase-matched two-crystal source generating polarization-entangled photon pairs at 809 nm and 1555 nm. We also show how the single-photon quantum channel at 1555 nm and a classical synchronization signal gating the single photon detector at the receiving side can be multiplexed in the same optical fiber of length 27 km by means of wavelength division multiplexers (WDM) having 100 GHz (0.8 nm) spacing between channels. This illustrates bow single-photon quantum communication applications is compatible with current high-speed optical networks.
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| 19. |
- Wang, Qin, et al.
(författare)
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1550 nm transmissive/reflective surface-normal electroabsorption modulator arrays
- 2006
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Ingår i: Electronics Letters. - : Institution of Engineering and Technology (IET). - 0013-5194 .- 1350-911X. ; 42:1, s. 47-48
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Tidskriftsartikel (refereegranskat)abstract
- Arrays of surface-normal 1550 nm transmissive/reflective dual-function electroabsorption modulators based oil InGaAs/InAlAs coupled quantum wells are investigated for free-space and optical fibre communications. The modulators can readily be switched between transmissive or reflective mode by using a removable Au mirror, which provides flexibility in the optical system configuration for different applications. The modulators exhibit contrast ratio of 2:1 at 3 V driving bias and contrast ratio of 2:1 over 30 nm bandwidth at 6 V. The maximum contrast ratio of 4:1 is achieved at a 12 V driving voltage.
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| 20. |
- Wang, Qin, et al.
(författare)
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Arrays of vertical-cavity electroabsorption modulators for parallel signal processing
- 2005
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Ingår i: Optics Express. - 1094-4087. ; 13:9, s. 3323-3330
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Tidskriftsartikel (refereegranskat)abstract
- Vertical-cavity multiple quantum well electroabsorption modulators (EAM) offer gigahertz modulation speeds, insensitivity to light polarisation and can be integrated into large arrays. They are therefore good candidates for efficient parallel signal processing architectures. We present high-performance 2 x 128 and 2 x 64 EAM arrays that were fabricated at 4" wafer-scale by using optimised fabrication and hybridisation processes. The arrays exhibit contrast ratios of 20: 1 with a voltage swing of 1 V, a maximum contrast ratio of 335: 1 for a 10 V bias and a modulation frequency in excess of 15 MHz.
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