Perova Tatiana, Shaganov Igor, Berwick Kevin
Department of Electronic and Electrical Engineering, Trinity College Dublin, The University of Dublin, 2 Dublin, Ireland.
Vavilov State Optical Institute, 199034 St.-Petersburg, Russia.
Materials (Basel). 2020 Jan 31;13(3):631. doi: 10.3390/ma13030631.
The optical constant of bulk metal is used to determine the dispersion of the local field under one-dimensional (1D), two-dimensional (2D) and three-dimensional (3D) confinement. 3D confinement, expressed as ε 2 m i c ( ω 3 D ) , corresponds to the dielectric loss spectra of spherical particles with a diameter, , much less than the wavelength of the beam used to measure the spectrum ( << λ). Excellent agreement with the results of Mie theory and experimental data for solid colloids within alkali halide crystals was observed. The function expressed as ε 2 m i c ( ω 1 D ) allows the measurement of spectral micro-characteristics in the frequency range of the longitudinal collective motion of the free electrons. This corresponds to the spectrum of dielectric losses of bulk plasma oscillations. The function ε 2 m i c ( ω 2 D ) describes the spectra of the dielectric losses of surface plasma oscillations in thin metal films. It is shown that the peak positions of ε 2 m i c ( ω 3 D ) , ε 2 m i c ( ω 2 D ) and ε 2 m i c ( ω 1 D ) spectra for simple metals, viz. alkali metals as well as Al, Be, Mg, Ga, In, Sn and Si, are in agreement with experimental results from electron-energy-loss spectroscopy and various optical techniques.
块状金属的光学常数用于确定一维（1D）、二维（2D）和三维（3D）限制下局部场的色散。3D限制表示为ε2mic(ω3D)，对应于直径远小于用于测量光谱的光束波长（<<λ）的球形颗粒的介电损耗光谱。观察到与碱金属卤化物晶体中固体胶体的米氏理论结果和实验数据具有极好的一致性。表示为ε2mic(ω1D)的函数允许在自由电子纵向集体运动的频率范围内测量光谱微观特征。这对应于块状等离子体振荡的介电损耗光谱。函数ε2mic(ω2D)描述了薄金属膜中表面等离子体振荡的介电损耗光谱。结果表明，简单金属（即碱金属以及Al、Be、Mg、Ga、In、Sn和Si）的ε2mic(ω3D)、ε2mic(ω2D)和ε2mic(ω1D)光谱的峰值位置与电子能量损失光谱和各种光学技术的实验结果一致。
