| 421. |
- Li, Xin, et al.
(författare)
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Enhancing fluorescence of quantum dots by silica-coated gold nanorods under one- and two-photon excitation
- 2010
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Ingår i: Optics Express. - 1094-4087. ; 18:11, s. 11335-11346
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Tidskriftsartikel (refereegranskat)abstract
- Nano-composites of quantum dots (QDs) and gold nanorods (GNRs) or silica-coated GNRs (GNRs_SiO2) were synthesized. The attached GNRs modify the excitation intensity and spontaneous emission of QDs through the surface plasmonic effects. The fluorescence from QDs is enhanced and can be optimized by modifying the thickness of silica coated on GNRs, under both one-and two-photon excitations. The measurements of fluorescence intensity and lifetime demonstrate that the enhancement may be attributed to the matching of the localized surface plasmon resonance of GNR to the excitation wavelength. In addition to enhancing QD-fluorescence in QD-GNR@SiO2, GNRs also present as an effective contrast agent for bio-imaging, through light scattering and or two-photon emission, as well as for photo-thermal therapy. The composite's multifunctional characteristics are highly valuable and to be exploited in bio-applications. (C) 2010 Optical Society of America
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| 422. |
- Li, Zongbao, et al.
(författare)
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High throughput trapping and arrangement of biological cells using self-assembled optical tweezer
- 2018
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Ingår i: Optics Express. - : OPTICAL SOC AMER. - 1094-4087. ; 26:26, s. 34665-34674
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Tidskriftsartikel (refereegranskat)abstract
- Lately, a fiber-based optical tweezer that traps and arranges the micro/nanoparticles is crucial in practical applications, because such a device can trap the biological samples and drive them to the designated position in a microfluidic system or vessel without harming them. Here, we report a new type of fiber optical tweezer, which can trap and arrange erythrocytes. It is prepared by coating graphene on the cross section of a microfiber. Our results demonstrate that thermal-gradient-induced natural convection flow and thermophoresis can trap the erythrocytes under low incident power, and the optical scattering force can arrange them precisely under higher incident power. The proposed optical tweezer has high flexibility, easy fabrication, and high integration with lab-on-a-chip, and shows considerable potential for application in various fields, such as biophysics, biochemistry, and life sciences.
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| 423. |
- Liang, Hao, et al.
(författare)
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InAs/GaAs quantum dot laser epitaxially grown on on-axis (001) GaAsOI substrate
- 2021
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Ingår i: Optics Express. - 1094-4087 .- 1094-4087. ; 29:23, s. 38465-38476
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Tidskriftsartikel (refereegranskat)abstract
- Quantum dot (QD) laser as a light source for silicon optical integration has attracted great research attention because of the strategic vision of optical interconnection. In this paper, the communication band InAs QD ridge waveguide lasers were fabricated on GaAs-on-insulator (GaAsOI) substrate by combining ion-slicing technique and molecular beam epitaxy (MBE) growth. On the foundation of optimizing surface treatment processes, the InAs/In0.13Ga0.87As/GaAs dot-in-well (DWELL) lasers monolithically grown on a GaAsOI substrate were realized under pulsed operation at 20 °C. The static device measurements reveal comparable performance in terms of threshold current density, slope efficiency and output power between the QD lasers on GaAsOI and GaAs substrates. This work shows great potential to fabricate highly integrated light source on Si for photonic integrated circuits.
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| 424. |
- Liljestrand, Charlotte, 1986-, et al.
(författare)
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Periodic poling of Rb-doped KTiOPO4 by coercive field engineering
- 2016
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Ingår i: Optics Express. - : Optical Society of America. - 1094-4087. ; 24:13, s. 14682-14689
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate fine-pitch periodic poling of bulk Rb-doped KTiOPO4 using a coercive field grating induced by ion-exchange. These samples were used for quasi phase matched (QPM) second harmonic generation at 795 nm with a normalized conversion efficiency of 1.7% W−1cm−1. Additionally, the ion-exchange introduced a refractive index change over the sample thickness resulting in a phasematching wavelength shift of 0.21 nm, adding extra tunability to the QPM device.
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| 425. |
- Lim, Y. J., et al.
(författare)
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Effects of three-dimensional polymer networks in vertical alignment liquid crystal display controlled by in-plane field
- 2014
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Ingår i: Optics Express. - : The Optical Society. - 1094-4087. ; 22:9, s. 10634-10641
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Tidskriftsartikel (refereegranskat)abstract
- Polymer network in vertical alignment liquid crystal cell driven by in-plane field (VA-IPS) is formed in three dimensions to achieve fast response time and to keep the liquid crystal alignment even when an external pressure is applied to the cell. The network formed by UV irradiation to vertically aligned liquid crystal cell with reactive mesogen does not disturb a dark state while exhibiting very fast decaying response time less than 2ms in all grey scales and almost zero pooling mura. The proposed device has a strong potential to be applicable to field sequential display owing to super-fast response time and flexible display owing to polymer network in bulk which supports a gap between two substrates. (C) 2014 Optical Society of America
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| 426. |
- Lin, Huagang, et al.
(författare)
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Polymer-based planar waveguide chirped Bragg grating for high-resolution tactile sensing
- 2022
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Ingår i: Optics Express. - : Optica Publishing Group. - 1094-4087. ; 30:12, s. 20871-20882
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Tidskriftsartikel (refereegranskat)abstract
- A novel tactile sensor for two-dimensional force location measurements, based on polymer-based planar waveguide chirped Bragg gratings (PPCBGs) fabricated on sheet PMMA substrate, is presented. The planar waveguide and chirped Bragg grating are simultaneously generated using a KrF excimer laser and a phase mask covered by a quartz chrome mask. Location and magnitude of an applied force is measured by observing the change of the wavelength of a dip in the measured spectrum and a change in the reflectivity intensity. Experimental characterization indicates submillimeter spatial resolution of applied force in the range of 1-4 N with a sensitivity of 947.02 pm/mm.
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| 427. |
- Lin, Rui, et al.
(författare)
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Physical-layer network coding for passive optical interconnect in datacenter networks
- 2017
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Ingår i: Optics Express. - 1094-4087. ; 25:15, s. 17788-17797
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Tidskriftsartikel (refereegranskat)abstract
- We introduce physical-layer network coding (PLNC) technique in a passive optical interconnect (POI) architecture for datacenter networks. The implementation of the PLNC in the POI at 2.5 Gb/s and 10Gb/s have been experimentally validated while the gains in terms of network layer performances have been investigated by simulation. The results reveal that in order to realize negligible packet drop, the wavelengths usage can be reduced by half while a significant improvement in packet delay especially under high traffic load can be achieved by employing PLNC over POI.
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| 428. |
- Lin, Rui, et al.
(författare)
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Real-time 100 Gbps/λ/core NRZ and EDB IM/DD transmission over multicore fiber for intra-datacenter communication networks
- 2018
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Ingår i: Optics Express. - : OSA - The Optical Society. - 1094-4087. ; 26:8, s. 10519-10526
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Tidskriftsartikel (refereegranskat)abstract
- A BiCMOS chip-based real-time intensity modulation/direct detection spatial division multiplexing system is experimentally demonstrated for both optical interconnects. 100 Gbps/λ/core electrical duobinary (EDB) transmission over 1 km 7-core multicore fiber (MCF) is carried out, achieving KP4 forward error correction (FEC) limit (BER < 2E-4). Using optical dispersion compensation, 7 × 100 Gbps/λ/core transmission of both non-return-to-zero (NRZ) and EDB signals over 10 km MCF transmission is achieved with BER lower than 7% overhead hard-decision FEC limit (BER < 3.8E-3). The integrated low complexity transceiver IC and analog signal processing approach make such a system highly attractive for the high-speed intra-datacenter interconnects..
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| 429. |
- Lin, Xihong, et al.
(författare)
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Effect of alloying on the dynamics of coherent acoustic phonons in bismuth double perovskite single crystals
- 2021
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Ingår i: Optics Express. - : Optical Society of America. - 1094-4087. ; 29:5, s. 7948-7955
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Tidskriftsartikel (refereegranskat)abstract
- The bismuth double perovskite Cs2AgBiBr6 has been regarded as a potential candidate for lead-free perovskite photovoltaics. A detailed study on the coherent acoustic phonon dynamics in the pure, Sb- and T1-alloyed Cs2AgBiBr6 single crystals is performed to understand the effects of alloying on the phonon dynamics and band edge characteristics. The coherent acoustic phonon frequencies are found to be independent of the alloying, while the damping rates are highly dependent on the alloying. Based on the mechanism of coherent acoustic phonon damping, a technique has been successfully developed that can accurately extract the absorption spectra near the indirect band gap for these single crystals with coefficients on the order of 10(2) cm(-1). (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
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| 430. |
- Lin, Zijian, et al.
(författare)
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Low-cost, high-speed multispectral imager via spatiotemporal modulation based on a color camera
- 2023
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Ingår i: Optics Express. - : Optica Publishing Group. - 1094-4087. ; 31:25, s. 42613-42623
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Tidskriftsartikel (refereegranskat)abstract
- Spectral imaging is a powerful tool in industrial processes, medical imaging, and fundamental scientific research. However, for the commonly used spatial/spectral-scanning spectral imager, the slow response time has posed a big challenge for its employment in dynamic scenes. In this paper, we propose a spatiotemporal modulation concept and build a simple, low-cost spectral imager by combining a liquid crystal (LC) cell with a commercial color camera. By the synergic effect of temporal modulation of the LC materials and spatial modulation of the Bayer filter in a color camera, high-quality multispectral imaging is successfully demonstrated with a high rate of 8 Hz, far beyond the counterparts. Experimental results show that even with three tuning states of the LC material, optical signals with a 10-nm band can be resolved in the range between 410 and 700 nm by this method, overcoming the tradeoff between spectral resolution and time resolution. As a proof of demonstration, we present its potential usage for metamerism recognition, showing superiority over traditional color cameras with more spectral details. Considering its low cost, miniaturization and monolithic-integration ability on color sensors, this simple approach may bring the spectral imaging technology closer to the consumer market and even to ubiquitous smartphones for health care, food inspection and other applications.
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