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Four channel optical demultiplexer based on L2 photonic crystal microcavity 基于L2光子晶体微腔的四通道光解复用器
IF 0.6 4区 物理与天体物理 Q4 Materials Science Pub Date : 2022-01-01 DOI: 10.37190/oa220411
Merzoug Ammari, A. Benmerkhi, M. Bouchemat
The wavelength demultiplexing is a particularly important function in integrated optics and can be realized using photonic crystals. The aim is to extract accurately the wavelengths in a data flux. In this work, we investigate a new topologies of wavelength demultiplexing based on two-dimensional photonic crystals constituted of dielectric rods spread in a square network. The studied demultiplexer is based on optical filters with optimized parameters in order to extract four different wavelengths in the vicinity of frequencies corresponding to communication windows. It was found that the crosstalk between the structure channels of the demultiplexer are in the range of –19.19 and –44.1 dB and the channel spacing is equal to 0.96 nm. The simulation results presented in this paper are performed and analyzed using the FDTD method.
波长解复用是集成光学中一个特别重要的功能,可以用光子晶体来实现。目的是准确地提取数据流中的波长。在这项工作中,我们研究了一种基于介电棒构成的二维光子晶体的波长解复用新拓扑。所研究的解复用器是基于优化参数的光滤波器,以提取通信窗口对应频率附近的四个不同波长。结果表明,该解复用器结构通道间的串扰在-19.19 ~ -44.1 dB范围内,通道间距为0.96 nm。利用时域有限差分法对本文给出的仿真结果进行了验证和分析。
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引用次数: 1
Nanoblocks embedded in L-shaped nanocavity of a plasmonic sensor for best sensor performance 纳米块嵌入等离子体传感器的l型纳米腔中,以获得最佳的传感器性能
IF 0.6 4区 物理与天体物理 Q4 Materials Science Pub Date : 2021-01-01 DOI: 10.37190/OA210109
M. A. Butt, N. Kazanskiy
In this work, we proposed a highly sensitive design of a plasmonic sensor which is formed by embedding a periodic array of nanoblocks in L-shaped cavity formed by the metal–insulator–metal waveguide. The nanoblocks are placed in the strong electric field confinement region to further enhance its strength by confining it to a small area. To validate the study, the spectral characteristics of the proposed sensor design is compared to the spectral characteristics of a standard design having the same geometric parameters excluding nanoblocks in the cavity. The study shows that the incorporation of 5 nanoblocks of length 25 nm in the cavity can provide best performance indicators in the form of sensitivity, figure of merit and Q-factor. The sensitivity, figure of merit and Q-factor of the proposed sensor design is 1065 nm/RIU, 251.17 and 343.4 which is significantly higher than the standard L-shape resonator design. The sensor design can be developed with a single fabrication step. Due to the ease of fabrication and the highly responsive nature of the design, it can be used in biomedical applications.
在这项工作中,我们提出了一种高灵敏度的等离子体传感器设计,该传感器通过在金属-绝缘体-金属波导形成的l形腔中嵌入纳米块的周期性阵列而形成。纳米块被放置在强电场约束区内,通过将其限制在一个小区域内进一步提高其强度。为了验证该研究,将所提出的传感器设计的光谱特征与具有相同几何参数的标准设计的光谱特征进行了比较,不包括腔中的纳米块。研究表明,在腔体中掺入5个长度为25 nm的纳米块可以提供最佳的灵敏度、优值和q因子等性能指标。该传感器的灵敏度、优值和q因子分别为1065 nm/RIU、251.17和343.4,显著高于标准l型谐振器设计。传感器的设计可以通过一个单一的制造步骤来开发。由于易于制造和高度响应的设计性质,它可以用于生物医学应用。
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引用次数: 8
Investigation of a tunable and switchable multi-wavelength bidirectional Brillouin-erbium fiber ring laser 可调谐可切换多波长双向布里渊-铒光纤环形激光器的研究
IF 0.6 4区 物理与天体物理 Q4 Materials Science Pub Date : 2021-01-01 DOI: 10.37190/oa210306
F. Wang, R.Y. Yuan
A multi-wavelength bidirectional Brillouin-erbium fiber ring laser with switchable Brillouin frequency spacing (BFS) is proposed and experimentally demonstrated. In the presented Brillouin-erbium ring laser, including an optical amplifier and a highly nonlinear fiber, and without any optical isolator, due to Rayleigh scattering, stimulated Brillouin scattering, and cascaded four-wave mixing initiated successively by the Brillouin pump (BP) light, the odd- and even-order Stokes lines are generated and circulate in the opposite direction in the ring cavity. The BP light and Stokes-induced Rayleigh backscattering light also simultaneously circulate in the ring cavity. Only by adjusting BP power, the gain competition between Brillouin based Stokes and cavity modes’ oscillation can be controlled, the laser output can be conveniently switched between single BFS and odd- or even-order double BFS. In addition, under the certain BP power conditions, the proposed multi-wavelength Brillouin-erbium fiber laser also can realize switchable odd- or even-order Stokes generation and Stokes generation with single BFS, with an increasing wavelength number in turn, only by simply adjusting pump power of the erbium-doped fiber amplifier. Stability and wavelength tunability of the proposed multi-wavelength bidirectional Brillouin-erbium fiber ring laser are also investigated, respectively.
提出了一种布里渊频率间隔可切换的多波长双向布里渊-铒光纤环形激光器,并进行了实验验证。本文提出的布里渊-铒环形激光器,包括光放大器和高度非线性光纤,没有任何光隔离器,由于瑞利散射、受激布里渊散射和布里渊泵浦(BP)光相继引发的级联四波混频,产生奇阶和偶阶斯托克斯线,并在环形腔中反向循环。BP光和stokes诱导的瑞利后向散射光也同时在环形腔内循环。只有通过调整BP功率,才能控制基于布里渊的Stokes增益竞争和腔模振荡,才能方便地在单次BFS和奇或偶次双BFS之间切换激光输出。此外,在一定BP功率条件下,只需简单调整掺铒光纤放大器的泵浦功率,所提出的多波长布里因-铒光纤激光器还可以实现奇阶或偶阶Stokes生成和单BFS的Stokes生成切换,且波长数依次增加。研究了多波长双向布里渊-铒光纤环形激光器的稳定性和波长可调性。
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引用次数: 0
Dual-parameter sensing characteristics of a single fiber Bragg grating half-pasted by 1C-LV epoxy under different curing c - lv环氧树脂半粘贴单光纤布拉格光栅在不同固化下的双参数传感特性
IF 0.6 4区 物理与天体物理 Q4 Materials Science Pub Date : 2021-01-01 DOI: 10.37190/oa210307
Hong Li, Haoyue Zhang, Yanming Song, Fanyong Meng, Lianqing Zhu
A novel technology for the simultaneous and independent measurement of dual parameters is proposed and experimented. By using a single fiber Bragg grating half-pasted by 1C-LV epoxy under different curing conditions, the sensor structure is designed such that the reflective single-peak spectrum splits into a twin-peak spectrum, which makes the FBG spectrum form a natural spectral peak splitting bias. A measurement limitation exists in the FBG sensor packaging at room temperature, which can be solved by the high-temperature cured packaging method. To verify the validity of the theory and methodology, the experimental system is used. In the range from –1000 to +1000 με and from 35 to 75°C, the Bragg wavelength change is relative linear to the strain and temperature. The temperature and strain variations can be independently and simultaneously measured using the split peak, and the deviations of the FBG sensor are ±1°C and ±5 με, respectively. This single FBG sensor can realize dual-parameter measurement, which is valuable for narrow-space health monitoring.
提出了一种同时独立测量双参数的新技术,并进行了实验。利用c - lv环氧树脂在不同固化条件下半粘贴的单光纤布拉格光栅,设计了传感器结构,使反射单峰光谱分裂为双峰光谱,使FBG光谱形成自然的谱峰分裂偏置。光纤光栅传感器在室温下封装存在测量限制,采用高温固化封装方法可以解决这一问题。为了验证理论和方法的有效性,采用了实验系统。在-1000 ~ +1000 με和35 ~ 75℃范围内,Bragg波长的变化与应变和温度呈相对线性关系。利用劈裂峰可以同时独立测量温度和应变的变化,FBG传感器的偏差分别为±1°C和±5 με。该传感器可实现双参数测量,对窄空间健康监测具有重要的应用价值。
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引用次数: 1
Influence of dispersion slope on soliton spectral tunneling in photonic crystal fiber 色散斜率对光子晶体光纤孤子光谱隧穿的影响
IF 0.6 4区 物理与天体物理 Q4 Materials Science Pub Date : 2021-01-01 DOI: 10.37190/oa210309
Yunxia Yang, Hua Yang, Xiongfeng Tong, Saili Zhao, Shuyuan Chen
We report a numerical investigation of how the dispersion slope affects the soliton spectral tunneling (SST) in a photonic crystal fiber with three zero dispersion wavelengths. It is discovered that a larger dispersion slope makes group-velocity mismatch between the initial soliton and the transferred wave thereby suppressing the SST effect, while a proper decrease of the dispersion slope enhances the SST effect to widen a supercontinuum range. Besides, we find a soliton-like leaking dispersion wave, which can sustain information and energy for a short time within a particular spectral range.
本文报道了色散斜率对具有三个零色散波长的光子晶体光纤中孤子光谱隧穿(SST)的影响。发现较大的色散斜率会使初始孤子与传递波之间的群速度不匹配,从而抑制海温效应,而适当减小色散斜率会增强海温效应,从而扩大超连续谱范围。此外,我们还发现了一种类似孤子的泄漏色散波,它可以在特定的光谱范围内短时间维持信息和能量。
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引用次数: 1
Characterisation of nano-thin film GO/TiO2 layers for Kretschmann-based surface plasmon resonance visible sensing using FDTD method kretschmann基表面等离子体共振可见光传感用纳米薄膜GO/TiO2层的FDTD表征
IF 0.6 4区 物理与天体物理 Q4 Materials Science Pub Date : 2021-01-01 DOI: 10.37190/oa210409
N. B. Khairulazdan, R. Mohamed, D. Berhanuddin, P. Menon
Kretschmann-based surface plasmon resonance (K-SPR) is suitable for biomolecular sensing which provides label-free and quick detection results with real-time analysis. In this work, we have investigated the effect of graphene oxide (GO) with titanium dioxide (TiO2) thin films that are placed in hybrid above metal layers such as gold (Au), silver (Ag) and copper (Cu) with the presence of chromium (Cr) as an adhesive layer. The thickness of the Au, Ag and Cu metal thin films were optimized to 40, 30 and 30 nm, respectively, with a fixed thickness of GO of 2 nm and TiO2 of 1.9 nm. The sensing was evaluated for SPR excitation at three different visible wavelengths of 633, 670 and 785 nm. The performance of sensing was analyzed based on the reflectance intensity and full-width at half-maximum (FWHM) of the spectrum using the finite-difference time-domain (FDTD) method. The sensitivity was calculated for analyte sensing in dielectric mediums of air versus water. The sensitivity increment percentage (%ΔS) was determined when comparing analyte detection using Cr/metal and Cr/metal/GO/TiO2 sensor structures. The highest sensitivity of 94.51 deg/RIU was achieved for Cr/Cu/GO/TiO2 K-SPR sensor at 633 nm wavelength.
基于kretschmann的表面等离子体共振(K-SPR)技术适用于生物分子传感,可提供无标记、快速的检测结果和实时分析。在这项工作中,我们研究了氧化石墨烯(GO)与二氧化钛(TiO2)薄膜的效果,这些薄膜被放置在金(Au)、银(Ag)和铜(Cu)等金属层的杂化层上,铬(Cr)作为粘合层存在。Au、Ag和Cu金属薄膜的厚度分别优化为40、30和30 nm,其中GO的固定厚度为2 nm, TiO2的固定厚度为1.9 nm。在633、670和785 nm三种不同的可见光波长下对SPR激发进行了检测。利用时域有限差分(FDTD)方法分析了基于光谱反射强度和半最大值全宽度的传感性能。计算了分析物在空气和水介质中的灵敏度。通过比较Cr/metal和Cr/metal/GO/TiO2传感器结构对分析物的检测,确定灵敏度增量百分比(%ΔS)。在633 nm波长处,Cr/Cu/GO/TiO2 K-SPR传感器的灵敏度最高,为94.51°/RIU。
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引用次数: 0
Comparison of near horizontal heterophoria tests in free space and with phoropter 自由空间近水平暗差试验与有光差试验的比较
IF 0.6 4区 物理与天体物理 Q4 Materials Science Pub Date : 2021-01-01 DOI: 10.37190/oa210204
Katarzyna Perz-Juszczyszyn, M. Feltzke, Katarzyna Dubas, W. C. Maples, B. Kolodziejczak, H. Buczkowska
Background: Measurements of phoria at near are important elements of the optometric assessment of binocular vision. It is important to know if different methods of measuring a phoria are interchangeable. This study was designed to compare phoria measures using in-phoropter (von Graefe) and in free space methods (Howell card). Methods: The study was conducted with 70 pre-presbyopic subjects, aged 23–35 years. Both near the von Graefe and near Howell card horizontal dissociated phorias along and with gradient +1.00 D and –1.00 D phorias were measured for each technique. Results: The mean values of the near dissociated phoria, for both test conditions (von Graefe and Howell card) showed a slight deviation in the two measures with von Graefe measures being generally more exophoric. The mean value of the phoropter phoria was 1.97 ∆ base-in and in free space, the value was 0.9 ∆ base-in. The phoropter phoria with the +1.00 D gradient was 5.24 ∆ base-in, and in free space, 2.73 ∆ base-in. Measurements of the phorometric phoria with a gradient of –1.00 D gave a mean of 0.42 ∆ base-out and 0.94 ∆ base-out in free space. The near phoria measures were significantly different for the basic near measure (p = 0.01) and for the +1.00 D gradient (p = 0.000002) but not for the –1.00 D measure (p = 0.36). Conclusion: The results of the differences in the near horizontal phoria in free space and in- phoropter were significantly different for the basic measure and for the +1.00 D gradient. The findings between the two methods of testing should therefore not be treated as equivalent or convertible. Each test method should have separate means and ranges established.
背景:近视距的测量是双眼视力验光评估的重要因素。重要的是要知道测量焦距的不同方法是否可以互换。本研究的目的是比较光镜内法(von Graefe)和自由空间法(Howell card)的焦距测量。方法:对70名年龄23 ~ 35岁的老花眼前期受试者进行研究。分别测量了von Graefe和Howell卡片附近沿+1.00 D和-1.00 D梯度水平分离的视界。结果:在两种测试条件下(von Graefe卡和Howell卡),近解离光的平均值在两种测量中显示出轻微的偏差,其中von Graefe测量通常更外显。光镜的平均值为1.97∆base-in,自由空间的平均值为0.9∆base-in。梯度为+1.00 D时,光度计的光度为5.24∆base-in,自由空间时,光度为2.73∆base-in。梯度为-1.00 D的光度测量的平均值为0.42,自由空间的平均值为0.94。基本近距离测量(p = 0.01)和+1.00 D梯度(p = 0.000002)的近距离测量差异显著,但-1.00 D测量无显著差异(p = 0.36)。结论:自由空间近水平视距与垂直视距的差异在基本测量和+1.00 D梯度下有显著性差异。因此,两种测试方法之间的结果不应被视为等同或可转换。每种测试方法都应该有单独的平均值和范围。
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引用次数: 0
Q-switched partially coherent lasers with controllable spatial coherence 可控空间相干的调q部分相干激光器
IF 0.6 4区 物理与天体物理 Q4 Materials Science Pub Date : 2021-01-01 DOI: 10.37190/oa210208
Yushuang Wang, Xuanxuan Ji, Ziyang Chen, Jixiong Pu
We develop a Q-switched degenerate laser, delivering a partially coherent light pulse of duration about 16 ns. The spatial coherence of the output laser pulse can be varied by tuning the spatial filter inside the laser resonator, and the oscillating transverse mode structure can be determined by measuring the degree of coherence of the output laser pulse. It is shown that the larger is the diameter of the spatial filter, the more are the oscillating transverse modes, and the lower is the degree of coherence. Based on coherent-mode representation for the partially coherent source, we can estimate the transverse mode contribution to the output partially coherent laser. The experimental results on suppressing speckle demonstrate that the generated partially coherent light possesses the characteristics of rapid reduction of spatial coherence, making it an ideal source for high-speed imaging and ranging applications.
我们开发了一种调q简并激光器,提供持续时间约16 ns的部分相干光脉冲。通过调节激光谐振腔内部的空间滤波器可以改变输出激光脉冲的空间相干性,通过测量输出激光脉冲的相干度可以确定振荡的横模结构。结果表明,空间滤波器直径越大,振荡横模越多,相干度越低。基于部分相干源的相干模式表示,我们可以估计出横向模式对输出部分相干激光的贡献。抑制散斑的实验结果表明,产生的部分相干光具有空间相干性快速降低的特点,是高速成像和测距应用的理想光源。
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引用次数: 2
FSO system performance analysis based on novel Gamma–Chi-square irradiance PDF model 基于新型γ -卡方辐照度PDF模型的FSO系统性能分析
IF 0.6 4区 物理与天体物理 Q4 Materials Science Pub Date : 2021-01-01 DOI: 10.37190/oa210303
J. Todorovic, P. Spalevic, S. Panic, Bojana Milosavljević, Milan Gligorijevic
In order to provide a novel analytically traceable free space optics (FSO) channel model for describing turbulence based irradiance fluctuations, following basic scintillation theory principles, we have derived closed-form expression for probability density function (PDF) of a new statistical Gamma–Chi-square model. Further, capitalizing on provided model, error performances of FSO system over on–off keying (OOK) transmission scheme both in the presence of atmospheric turbulence and misalignment fading (pointing error) is investigated. For both cases, the average bit error rate (ABER) at the receiving side of the system is determined in an analytically closed form. The results are graphically presented in order to analyze the impact of different levels of turbulence, as well as other relevant parameters, on the quality of the received signal in the OOK modulated FSO system.
为了提供一种新的解析可追溯的自由空间光学(FSO)通道模型来描述基于湍流的辐照度波动,遵循闪烁理论的基本原理,我们推导了一种新的统计伽玛-卡方模型的概率密度函数(PDF)的封闭表达式。此外,利用所提供的模型,研究了FSO系统在大气湍流和不对准衰落(指向误差)存在下的开关键控(OOK)传输方案的误差性能。对于这两种情况,系统接收端的平均误码率(ABER)以解析封闭形式确定。为了分析不同湍流水平以及其他相关参数对OOK调制FSO系统接收信号质量的影响,结果以图形形式呈现。
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引用次数: 1
Broadband fluorescence emission and laser demonstration in large mode waveguide structure in Yb3+ doped germanate glass 掺Yb3+锗酸盐玻璃大模波导结构中的宽带荧光发射及激光演示
IF 0.6 4区 物理与天体物理 Q4 Materials Science Pub Date : 2021-01-01 DOI: 10.37190/OA210106
M. Khalid
A stable composition (against crystallization) of germanate glass doped with Yb3+ for mid-infrared laser applications is presented. Broad emission spectrum of Yb3+ was obtained for the fabricated glass. Laser operation was demonstrated in 13 mm long waveguide written in the glass using a femtosecond laser operating at 524 nm center wavelength sending 250 fs ultrashort pulses. The resulting CW laser operated at 1.04 μm in the fundamental mode of the waveguide. The propagation loss through the waveguide was 0.6 dB/cm at 1550 nm for 45 μm diameter of the modified structure. The mode analysis of the developed waveguide structure is also presented in COMSOL Multiphysics to study the electric field distribution through different modes of propagation in the waveguide and the confinement loss associated to them.
提出了一种用于中红外激光的掺Yb3+锗酸盐玻璃的稳定成分(抗结晶)。制备的玻璃具有较宽的Yb3+发射光谱。利用中心波长为524 nm的飞秒激光器,发射250 fs的超短脉冲,在玻璃上书写的13 mm长波导中演示了激光操作。得到的连续波激光器工作在1.04 μm的波导基模下。在直径为45 μm的1550 nm处,波导的传输损耗为0.6 dB/cm。在COMSOL Multiphysics中对所开发的波导结构进行了模态分析,研究了波导中不同传播模式下的电场分布以及与之相关的约束损耗。
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引用次数: 1
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Optica Applicata
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