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oe1(光电查) - 科学论文

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出版时间
  • 2018
研究主题
  • Display Metrology
  • dSiPM
  • Quanta Image Sensor
  • CMOS
  • QIS
  • Complementary Metal Oxide Semiconductor
  • Digital Silicon Photo-Multiplier
  • Single Photon Avalanche Diode
  • SPAD
应用领域
  • Optoelectronic Information Science and Engineering
机构单位
  • The University of Edinburgh
  • STMicroelectronics Imaging Division
1265 条数据
?? 中文（中国） ▾

  • Polarization-controlled and single-transverse-mode vertical-cavity surface-emitting lasers with eye-shaped oxide aperture

    摘要： We presented a single-transverse-mode and single-polarization vertical-cavity surface-emitting laser (VCSEL) with an eye-shaped oxide aperture, obtained by enhanced anisotropic oxidation of oxide layer. For apertures with dimensions of 2 ' 4.6 and 3 ' 6 μm2, the orthogonal polarization suppression ratio (OPSR) of the VCSEL was 22 and 19 dB, respectively. A single-mode suppression ratio (SMSR) of more than 25 dB at an output power of 0.5 mW was also achieved for the VCSEL with aperture dimension of 2 ' 4.6 μm2. We believe that the proposed method to realize the mode and polarization control of VCSELs has great potential in future applications. ? 2018 The Japan Society of Applied Physics

    关键词： anisotropic oxidation,single-transverse-mode,VCSEL,single-polarization,eye-shaped oxide aperture

    更新于2025-11-28 14:24:03

  • Carboxyl graphene oxide solution saturable absorber for femtosecond mode-locked erbium-doped fiber laser

    摘要： The carboxyl-functionalized graphene oxide (GO-COOH) is a kind of unique two-dimensional (2D) material and possesses excellent nonlinear saturable absorption property and high water-solubility. In this paper, we prepare saturable absorber (SA) device by depositing GO-COOH nanosheets aqueous solution on a D-shaped ?ber. The modulation depth (MD) and saturable intensity of the SA are measured to be 9.6% and 19 MW/cm2, respectively. By inserting the SA into the erbium-doped ?ber (EDF) laser, a passively mode-locked EDF laser has been achieved with the spectrum center wavelength of 1562.76 nm. The pulse duration, repetition rate, and the signal-to-noise ratio (SNR) are 500 fs, 14.79 MHz, and 80 dB, respectively. The maximum average output power is measured to be 3.85 mW. These results indicate that the GO-COOH nanosheets SA can be used as a promising mode locker for the generation of ultrashort pulses.

    关键词： nonlinear optical materials,mode-locked pulse,?ber lasers,carboxyl graphene oxide

    更新于2025-11-28 14:24:03

  • Mode-locked thulium doped fiber laser with zinc oxide saturable absorber for 2?μm operation

    摘要： In this work, a 2.0-micron mode-locked thulium doped fiber laser is demonstrated using zinc oxide (ZnO) as the saturable absorber (SA) in a thulium doped fiber laser (TDFL). The ZnO nanorods was prepared by the facile hydrothermal method, and then embedded in polyethylene oxide composite film to form the SA. The laser is capable of generating soliton pulses at a central wavelength of 1945.45 nm with a 3-dB bandwidth of 3.47 nm. The pulse width is measured to be 1.395 ps, only slightly higher than the calculated transform-limited pulse width of 1.15 ps. The peak power of the generated mode-locked pulses is then calculated to be as high as 41.88 W, with a signal-to-noise ratio of 50.5 dB. The fabricated ZnO film in this work would allow the generation of mode-locked pulses, which could be useful for applications in spectroscopy and medicine due to the eye-safe and highly sensitive nature of the 2.0-micron region.

    关键词： pulse fiber laser,mode-locking,Thulium,zinc oxide

    更新于2025-11-28 14:24:03

  • Mode-locking in Er-doped fiber laser with reduced graphene oxide on a side-polished fiber as saturable absorber

    摘要： In this work, the generation of highly stable mode-locked pulses from a side-polished fiber (SPF) embedded with graphene oxide (rGO) nanoparticles (NPs) is proposed and demonstrated. The rGO NPs are obtained from a graphene oxide solution prepared using Hummer’s technique, before being reduced by a hydrothermal route. The rGO NPs, suspended in the form of a solution, are then drop-casted onto the SPF. The SPF is fabricated by polishing away the cladding layer of a single-mode fiber section, leaving the core exposed and allowing the evanescent field of the signal propagating through the fiber to interact directly with the NPs. The SPF is integrated into an erbium doped fiber laser (EDFL) cavity, and the strong nonlinear optical response and spectral filtering by the rGO NPs as well as total anomalous dispersion of the laser cavity generates highly stable soliton mode-locked pulses with visible Kelly’s sidebands at 1544.02 nm. The output pulses have a pulse repetition rate of 16.79 MHz and pulse duration of 1.17 ps throughout the mode-locking operation range of 64.44–280.5 mW. The rGO NP coated SPF in this work demonstrates the viability and performance of the SPF for mode-locked pulse generation via evanescent field interactions.

    关键词： Side polished fiber,Reduced graphene oxide,Mode-locked fiber laser,Saturable absorber

    更新于2025-11-28 14:23:57

  • Ultrasensitive tantalum oxide nano-coated long-period gratings for detection of various biological targets

    摘要： In this work we discussed a label-free biosensing application of long-period gratings (LPGs) optimized in refractive index (RI) sensitivity by deposition of thin tantalum oxide (TaOx) overlays. Comparing to other thin film and materials already applied for maximizing the RI sensitivity, TaOx offers good chemical and mechanical stability during its surface functionalization and other biosensing experiments. It was shown theoretically and experimentally that when RI of the overlay is as high as 2 in IR spectral range, for obtaining LPGs ultrasensitive to RI, the overlay’s thickness must be determined with subnanometer precision. In this experiment the TaOx overlays were deposited using Atomic Layer Deposition method that allowed for achieving overlays with exceptionally well-defined thickness and optical properties. The TaOx nano-coated LPGs show RI sensitivity determined for a single resonance exceeding 11,500 nm/RIU in RI range nD=1.335-1.345 RIU, as expected for label-free biosensing applications. Capability for detection of various in size biological targets, i.e., proteins (avidin) and bacteria (Escherichia coli), with TaOx-coated LPGs was verified using biotin and bacteriophage adhesin as recognition elements, respectively. It has been shown that functionalization process, as well as type of recognition elements and target analyte must be taken into consideration when the LPG sensitivity is optimized. In this work optimized approach made possible detection of small in size biological targets such as proteins with sensitivity reaching 10.21 nm/log(ng/ml).

    关键词： protein detection,label-free biosensing,optical fiber sensor,tantalum oxide,bacteria detection,long-period grating,atomic layer deposition

    更新于2025-11-28 14:23:57

  • Graphene-Based Steganographicly Aptasensing System for Information Computing, Encryption and Hiding, Fluorescent Sensing and In Vivo Imaging of Fish Pathogens

    摘要： Inspired by information processing and communication of life based on complex molecular interactions, some artificial (bio)chemical systems have been developed for applications in molecular information processing or chemo/biosensing and imaging. However, little attention has been paid to simultaneously and comprehensively utilize the information computing, encoding and molecular recognition capabilities of molecular-level systems (such as DNA-based systems) for multifunctional applications. Herein, a graphene-based steganographicly aptasensing system was constructed for multifunctional application, which relies on specific molecular recognition and information encoding abilities of DNA aptamers (Aeromonas hydrophila and Edwardsiella tarda-binding aptamers as models) and the selective adsorption and fluorescence quenching capacities of graphene oxide (GO). Although graphene-DNA systems have been widely used in biosensors and diagnostics, our proposed graphene-based aptasensing system can not only be utilized for fluorescent sensing and in vivo imaging of fish pathogens (Aeromonas hydrophila and Edwardsiella tarda), but can also function as a molecular-level logic computing system where the combination of matters (specific molecules or materials) as inputs produces the resulting product (matter level) or fluorescence (energy level) changes as two outputs. More importantly and interestingly, our graphene-based steganographicly aptasensing system can also be served as a generally doubly cryptographic and steganographic system for sending different secret messages by using pathogen-binding DNA aptamers as information carriers, GO as a cover, a pair of keys: target pathogen as a public key, the encryption key used to encode or decode a message in DNA as a private key. Our study not only provides a novel nano-biosensing assay for rapid and effective sensing and in vivo imaging fish pathogens, but also demonstrates a prototype of (bio)molecular steganography as an important and interesting extension direction of molecular information technology, which is helpful in probably promoting the development of multifunctional molecular-level devices or machines.

    关键词： aptasensing,steganography,graphene oxide,DNA aptamer,encryption,fish pathogens,in vivo imaging,information hiding

    更新于2025-11-21 11:24:58

  • A carbon nanotube-iron (III) oxide nanocomposite as a cathode in dye-sensitized solar cells: Computational modeling and electrochemical investigations

    摘要： Here is the evaluating result on the applicability of the multi-walled carbon nanotube (MWCNT) and a-iron (III) oxide (a-Fe2O3) nanocomposite as a cathode material in dye-sensitized solar cells (DSCs). The morphology and the structure of the MWCNT/a-Fe2O3 nanocomposite have characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray elemental mapping analysis. Moreover, the electrochemical performance of the nanocomposite has studied toward the activity of Iˉ/I3ˉ redox couple which represents high current density, low peak-to-peak separation, low charge-transfer resistance, and almost 100% stable response signal. Furthermore, the computational modeling employing the molecular mechanics (MM) and the restricted-Hartree Fock/semiempirical parameterization (RHF/PM6) methods reveals that the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO), and the HOMO-LUMO energy gap of the modeled nanocomposite are as (cid:1)6.88, (cid:1)3.62, and 3.26 eV, respectively. These properties match with the electronic-level domino of the DSC structure. Finally, the DSC device has fabricated using N719-sensitized TiO2 photoanode and MWCNT/a-Fe2O3 counter electrode, presenting the open-circuit potential, the short-circuit current density, and the power-conversion ef?ciency of 0.7 V, 20.37 mA cmˉ2, and 6.0%, respectively. This study successfully approves the potential of the nanocomposite as a cathode material in iodine-based dye-sensitized solar cells.

    关键词： Dye-sensitized solar cell,Nanocomposite,Carbon nanotube,Molecular mechanics,RHF/PM6,Iron (III) oxide

    更新于2025-11-21 11:18:25

  • Synthesis of hybrid zinc-based materials from ionic liquids: a novel route to prepare active Zn catalysts for the photoactivation of water and methane

    摘要： A new and simple route for the preparation of zinc-based materials is proposed in this work. The synthesis of zinc oxide from the hydrolysis of imidazolium trichlorozincate ionic liquids (ILs) produces catalytic active nanostructured materials, where the size and shape (irregular particles, nanorods) are dependent on the synthetic conditions employed. Indeed, the hydrolysis of trichlorozincate ILs prepared by an equimolar ionic liquid:ZnCl2 ratio afforded irregular particles, while increasing the IL amount (2:1 and 4:1) drives to the formation of nanorods. These hybrid zinc oxide materials were able to promote the photoactivation of water and methane at 25 °C affording up to 1417 μmolH2.g-1.h-1 and up to 67 μmolCO2.g-1.h-1, respectively. Moreover, tuning the reaction conditions a microstructured zinc-based mineral named simonkolleite was prepared with the expected hexagonal-like morphology. This compound was also applied as an alternative and efficient photocatalyst in the activation of water (972 μmolH2.g-1.h-1) and methane (12.6 μmolCO2.g-1.h-1).

    关键词： Zinc oxide,photocatalysis,semiconductors,simonkolleite,ionic liquids,nanomaterials

    更新于2025-11-21 11:18:25

  • Investigation of temperature and frequency dependence of electrical conductivity and dielectric behavior in CuS and rGO capped CuS nanocomposites

    摘要： In this work, we develop a simple and low-cost strategy toward the one-pot synthesis of reduced graphene oxide (rGO) capped copper sulfide (CuS) nanocomposite through an obvious redox transformation reaction between Cu and graphene oxide (GO) without any additive. The prepared CuS and rGO capped CuS nanocomposite have been characterized by various physicochemical techniques for the observation of shape, morphology, and structure. It reveals the average size of the synthesized samples in the range of 10–30 nm with the hexagonal structure. The UV–vis absorption spectra exposed the strong absorption peak of CuS and rGO capped CuS composites in the range of NIR region was observed. The synthesized samples displayed high dielectric constant and electrical conductivity in a wide range of frequency (102–106 Hz). The effect of temperature on the electrical conductivity of the synthesized rGO capped CuS nanocomposite was also investigated. The excellent electrical conductivity performance is ascribed to the synergistic effect between CuS and rGO. As the temperature increases, the maximum electrical conductivity of rGO capped CuS composite was exponentially increased at high temperature. The synthesized composite with a high dielectric constant and electrical conductivity is a promising material in high capacitance, and further, it is used as electrode materials for supercapacitors and energy storage applications.

    关键词： electrical conductivity,temperature effect,CuS nanocomposites,reduced graphene oxide,dielectric constant

    更新于2025-11-21 11:18:25

  • Visualizing Nitric Oxide in Mitochondria and Lysosomes of Living Cells with N-Nitrosation of BODIPY-based Fluorescent Probes

    摘要： Nitric oxide (NO), a ubiquitous gasotransmitter which plays critical roles in cardiovascular, nervous, and immune systems related diseases, is closely related in the physiological and pathological processes of mitochondria and lysosomes. Thus, monitoring NO in mitochondria or lysosomes is very meaningful for NO related chemical biology. Herein, we rationally designed four NO probes, BDP-NO, Mito-NO-T, Mito-NO and Lyso-NO, based on BODIPY dye substituted at meso position with 5-amino-2-methoxy-phenyl scaffold. These four probes all showed fast fluorescence off-on response toward NO with excellent selectivity and high sensitivity with the detection limit of BDP-NO to reach 5.7 nM. We introduced triphenylphosphonium and morpholine moieties onto BODIPY scaffold respectively to enable organelle-targetability. MTT and flow cytometry assay demonstrated that the probes exhibited low cytotoxicity, which was beneficial to the biological application in living cells. Confocal fluorescence microscopy experiments confirmed excellent mitochondria targeting for Mito-NO and lysosome-targeting with Lyso-NO for the detection of NO in living cells.

    关键词： Fluorescent probes,Mitochondria-targeted,Lysosomes-targeted,BODIPY,Nitric oxide

    更新于2025-11-21 11:08:12