Author Affiliations
Abstract
1 School of Electrical Engineering and Computer Science, Louisiana State University, Baton Rouge, Louisiana 70803, USA
2 Center for Computation and Technology, Louisiana State University, Baton Rouge, Louisiana 70803, USA
3 Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, USA
We introduce a nanoplasmonic isolator that consists of a cylindrical resonator placed close to a metal-dielectric-metal (MDM) waveguide. The material filling the waveguide and resonator is a magneto-optical (MO) material, and the structure is under an externally applied static magnetic field. We theoretically investigate the properties of the structure and show that the cavity mode without MO activity splits into two modes when the MO activity is present. In addition, we find that the presence of the MDM waveguide leads to a second resonance due to the geometrical asymmetry caused by the existence of the waveguide. We also show that, when MO activity is present, the cavity becomes a traveling wave resonator. Thus, the transmission of the structure depends on the direction of the incident light, and the proposed structure operates as an optical isolator.
plasmonics metal optics magneto-optic systems Chinese Optics Letters
2021, 19(8): 083602
1 南开大学电子信息与光学工程学院现代光学研究所天津市微尺度光学信息技术科学重点实验室, 天津 300350
2 天津大学精密仪器与光电子工程学院精密测试技术及仪器国家重点实验室, 天津 300072
利用原子力显微镜(AFM)、荧光显微成像系统以及时间分辨单光子计数(TCSPC)系统,对金纳米球(AuNS)-银纳米线(AgNW)耦合结构纳米间隙内的量子点荧光自发辐射增强以及表面等离激元(SPP)传导特性进行研究。实验使用两种方式实现了金纳米球和银纳米线间的耦合。第一种方式为:将金纳米球和量子点的混合溶液及银纳米线溶液依次涂覆到SiO2基片上,寻找随机存在的金纳米球-银纳米线耦合结构。第二种方式为:利用AFM进行纳米操纵,在SiO2基片上实现了可控的金纳米球和银纳米线耦合结构。利用该结构,实现了最高达到611的量子点自发辐射速率增强因子,同时也观测到了被增强的荧光激发SPP沿银纳米线传导。利用COMSOL Multiphysics仿真软件,对金纳米球-银纳米线耦合结构附近不同位置和偏振的量子点自发辐射速率增强因子进行了模拟计算,并且和单个金纳米球、单根银纳米线附近量子点自发辐射速率增强因子进行了对比,结果表明金纳米球-银纳米线耦合结构能够获得更高的自发辐射速率增强因子。计算了量子点激发的银纳米线上SPP的场分布,得到了与实验相符的结果。
微纳光学 荧光 表面等离子体 金属光学 纳米结构 纳米操纵 中国激光
2020, 47(10): 1013001
1 上海大学理学院, 上海 200444
2 郑州师范学院物理与电子工程学院, 河南 郑州 450044
对太赫兹金属平行平板波导的最低阶横电(TE1)模式进行理论研究,并且在真实金属参数的条件下,推导出一个适用于太赫兹金属平行平板波导TE1模式有效折射率的近似表达式。首先对TE1模式进行基于有限元方法的数值模拟,并且将模拟结果与近似表达式所得的数值进行对比,验证理论推导的可行性。接着由误差分析表明所推导的近似表达式在整个太赫兹波段具有很高的精确度,并且具有适用频率范围广的特点。模拟仿真结果表明,该近似表达式对TE1模式的分析具有高度的适用性,将对金属平行平板波导的研究和应用起到一定的促进作用。
光学器件 波导 太赫兹波 金属光学 远红外 激光与光电子学进展
2020, 57(19): 192302
1 上海大学物理系,上海 200444
2 郑州师范学院物理与电子工程学院, 河南 郑州 450044
基于平行平板波导的TE1模式理论和电场是近似线偏振的假设,推导了余弦-高斯光束在平行平板波导中的电场传输表达式。在傍轴近似的条件下,余弦-高斯光束可以作为平行平板波导的一个基础解。当频率为0.35 THz时,对余弦-高斯光束在金属铜平行平板波导中的传输进行了数值模拟,结果表明模拟的幅值和相位与根据电场表达式所得结果符合得很好,同时也讨论了z轴方向上模拟的相位与理论结果的偏差和电场散度方程的完备性。
光学器件 平行平板波导 太赫兹波 金属光学 余弦-高斯光束 激光与光电子学进展
2019, 56(19): 192302
为了实现太赫兹高斯光束与双曲线形金属波导的高效耦合, 设计了一个渐变的椭圆-双曲线形金属波导连接器。此波导连接器的输入端是矩形的, 输出端是椭圆-双曲线形的。在渐变的过程中, 矩形金属波导的TE01模逐渐转变成双曲线形金属波导的椭圆偏振模。根据WKB近似, 这个缓慢渐变的波导消除了反射和散射, TE01模和椭圆偏振模的耦合效率可以高达94%。最终, 经过这个渐变连接器, 高斯光束和双曲线形金属波导的耦合效率可以提高到69.1%。
连接器 波导 远红外或太赫兹 金属光学 connector waveguides far infrared or terahertz metal optics 红外与激光工程
2019, 48(2): 0203003
1 中国科学院长春光学精密机械与物理研究所应用光学国家重点实验室, 吉林 长春 130033
2 中国科学院大学, 北京 100049
生命科学领域的研究需要对样本进行纳米量级的宽视场、实时动态观测。提出了一种基于金属光栅近场衍射增强的结构光照明技术, 该技术在传统e-pi显微镜的基础上引入金属光栅和空间光调制器；对该技术的亚波长成像性能进行了理论分析和数值分析。研究结果表明:在波长为520 nm、数值孔径为1.3的条件下, 该技术可以使半峰全宽的横向空间分辨率为65 nm, 相比于宽场照明显微分辨率提升了约3.7倍；该技术以其优异的亚波长成像性能在生命科学领域研究中具有潜在的应用价值。
显微 荧光显微 超分辨 表面等离子体 金属光学
中国科学院长春光学精密机械与物理研究所 应用光学国家重点实验室,长春 130033
经典的恢复算法不能有效地恢复被观测物的全频域信息, 空间频率的缺失导致超分辨图像伴有较为严重的旁瓣.本文提出利用最大后验概率(MAP)评估解决表面等离子体结构光照明技术中的光学旁瓣问题.结果表明MAP评估恢复算法可以有效恢复物质的高空间频率信息, 并且通过合理选择优化参数达到抑制光学旁瓣的目的.在波长520 nm, 数值孔径1.3下, 可获得半高全宽65 nm的横向分辨力, 约为传统荧光显微镜的3.6倍.该技术在生命科学观测中具有潜在应用价值.
显微 荧光显微 超分辨 表面等离子体 金属光学 图像重建技术 Microscopy Fluorescence microscopy Superresolution Surface plasmons Metal optics Image reconstruction techniques
Author Affiliations
Abstract
Department of Physics, East China University of Science and Technology, Shanghai 200237, China
A terahertz (THz) waveguide using a metallic nanoslit whose width is much smaller than the skin depth is analytically investigated. By taking some important physical properties into account, we derive a simple, yet accurate, expression for the effective index. We also study the changes in modal field and the attenuation coefficient in the whole THz region, and find some interesting physical properties. Finally, we verify that these theoretical analyses coincide with the rigorous numerical simulations. This research can be useful for various applications of THz waveguides made of metallic nanoslits.
240.6680 Surface plasmons 230.7370 Waveguides 260.3090 Infrared, far 260.3910 Metal optics Chinese Optics Letters
2016, 14(7): 072401
Author Affiliations
Abstract
1 McMaster University, Department of Electrical and Computer Engineering, Hamilton, Ontario L8S4K1, Canada
2 The American University in Cairo, Department of Physics, AUC Avenue, P. O. Box 74, New Cairo 11835, Egypt
In this paper we present a novel nanoantenna (nantenna) design for energy harvesting. The nantenna has an “E” shape and is placed on a SiO2 substrate. Its operation is based on the excitation of surface plasmon polaritons through the gold arms of the E shape. By varying the lengths and widths of the arms, two overlapping working bandwidths can be achieved. This results in a wideband behavior characterized by a full width at half-maximum of about 2.2 μm centered around 3.6 μm. Two orthogonal E nantennas are placed perpendicular to each other to realize a dual-polarized nantenna. This nantenna can receive the two incident polarizations at two separate gap locations with very high isolation. The proposed structure can be used in several energy harvesting applications, such as scavenging the infrared heat from the Earth and other hot objects, in addition to optical communications.crystals;Subwavelength structures, nanostructures;Resonance
Plasmonics Plasmonics Metal optics Metal optics Nanophotonics and photonic Nanophotonics and photonic Photonics Research
2015, 3(4): 04000140
Author Affiliations
Abstract
interdisciplinary Photonics Laboratories, School of Chemistry, The University of Sydney, NSW 2006, Australia
A large dynamic index measurement range (n =1 to n = 1.7) using surface plasmon resonance (SPR) shifts was demonstrated with a ZnSe prism at 632.8 nm, limited by the available high index liquid hosts. In contrast to borosilicate based SPR measurements, where angular limitations restrict solvent use to water and require considerable care dealing with Fresnel reflections, the ZnSe approach allows SPR spectroscopies to be applied to a varied range of solvents. An uncertainty in angular resolution between 1.5° and 6°, depending on the solvent and SPR angle, was estimated. The refractive index change for a given glucose concentration in water was measured to be n = (0.114 ± 0.007) /%[C6H12O6]. Given the transmission properties of ZnSe, the processes can be readily extended into the mid infrared.
Plasmonics surface plasmons surface waves scattering spectroscopy metal optics Photonic Sensors
2015, 5(3): 278–283
