Surface plasmon gap waveguide wcich creates stiongly enhanced and confined optical near-field

在利用SPGW进行光路设计时，最基本和最重要的参数之一是导波的传播常数。由于金属在光频区域是具有复介电常数的电介质物体，因此SPGW中的导波传播常数不可避免地具有复值，即，衰减常数和相位常数。利用实用技术激发导波，并研究激发导波在SPGW中的传播特性，对SPGW的实验研究具有重要意义。由于积分方程法常用于纳米光子学的数值模拟中，因此积分方程法计算传播常数的数值技术也是非常重要的。本文采用体积积分方程对高斯光束通过I形光阑激发的表面等离子体激元间隙波导（SPGW）中的导波进行了三维数值模拟。S中激发的光场 ...更多信息 PGW在实际条件下进行了研究。利用最小二乘拟合方法计算了模拟光场的复传播常数。传播常数的依赖性，即，的衰减和相位常数，对间隙的宽度和间隙的深度的SPGW的研究。使用上述结果，执行使用SPGW的三维（3D）成像模拟，作为实际条件下SPGW的高性能的示例。对纳米介质目标的成像仿真表明，该探针在照明模式、收集反射模式和收集模式下均能实现预期的成像效果，其分辨率与探针针尖直径基本一致。然而，大多数的模拟检查分辨率和尖端半径之间的关系，在NSOM中使用散射探头已经进行的假设，探头尖端近似由一个小的和孤立的球形物体的半径等于尖端半径。然而，在实际条件下，入射光不仅被尖端散射，而且额外的散射降低了分辨率。因此，在实际条件下，没有一个简单的球形探头尖端的假设下，NSOM的成像模拟仍然是重要的。为了确定PGP在本研究中实际条件下的特性和性能，在没有这种假设的情况下进行了模拟。少

In the design of optical circuits by using SPGW, one of the most fundamental and important parameters is the propagation constant of guided waves. Since the metals are dielectric objects with complex permittivity in the optical frequency region, the propagation constant of guided waves in the SPGW has complex value inevitably, i.e., attenuation constant and phase constant. The excitation of guided waves by the practical techniques and propagation characteristics of excited guided-waves in SPGW will be important for experimental study of SPGW. Numerical techniques of computation of propagation constants by integral equation method will be also important, because integral equation method are often used in the simulation in nanophotonics.The guided waves in the surface plasmon polariton gap waveguide (SPGW) excited by the Gaussian beam through the I-shaped aperture have been investigated by the three-dimensional simulations using a volume integral equation. Optical fields excited in the S … More PGW are investigated under practical conditions. The complex propagation constants are calculated from the simulated optical fields using the least-squares fitting. The dependence of the propagation constant, i.e., attenuation and phase constants, on the gap-width and on the gap-depth of SPGW is investigated. Using above-mentioned results, the three-dimensional (3D) imaging simulations using the SPGW are performed as an example of the high performance of the SPGW under practical conditions. Simulations of imaging for a nanometric dielectric object demonstrate that the probe functions as expected in illumination mode, collection-reflection mode, and collection mode with resolution approximately correspondent to the tip diameter of the probe.A number of 3D imaging simulations for NSOM using aperture and scattering probes under practical conditions have been reported. However, most simulations examining the relationship between resolution and tip radius in NSOM using a scattering probe have been performed on the assumption that the probe tip is approximated by a small and isolated spherical object with radius equal to the tip radius. However, under practical conditions, incident light is scattered not just by the tip, and the additional scatter degrades the resolution. Imaging simulations of NSOM under practical condition without the assumption of a simple spherical probe tip thus remain important. The simulations were conducted without such an assumption in order to determine the characteristics and performance of the PGP under practical conditions in this research. Less