Optical Properties of Ag and Cu
TL;DR: In this paper, experimental data for the optical constants of Ag and Cu extending to 25 eV are discussed in terms of three fundamental physical processes: (1) free-electron effects, (2) interband transitions, and (3) collective oscillations.
Abstract: Experimental data for the optical constants of Ag and Cu extending to 25 eV are discussed in terms of three fundamental physical processes: (1) free-electron effects, (2) interband transitions, and (3) collective oscillations. Dispersion theory is used to obtain an accurate estimate of the average optical mass characterizing the free-electron behavior over the entire energy range below the onset of interband transitions. The values are ${m}_{a}=1.03\ifmmode\pm\else\textpm\fi{}0.06$ for Ag and 1.42\ifmmode\pm\else\textpm\fi{}0.05 for Cu. The interband transitions to 11 eV are identified tentatively using Segall's band calculations. Plasma resonances involving both the conduction band and $d$ electrons are identified and described physically.
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TL;DR: The reflectance and the phase change on reflection from semiconductor-metal interfaces (including the case of metallic multilayers) can be accurately described by use of the proposed models for the optical functions of metallic films and the matrix method for multilayer calculations.
Abstract: We present models for the optical functions of 11 metals used as mirrors and contacts in optoelectronic and optical devices: noble metals (Ag, Au, Cu), aluminum, beryllium, and transition metals (Cr, Ni, Pd, Pt, Ti, W). We used two simple phenomenological models, the Lorentz-Drude (LD) and the Brendel-Bormann (BB), to interpret both the free-electron and the interband parts of the dielectric response of metals in a wide spectral range from 0.1 to 6 eV. Our results show that the BB model was needed to describe appropriately the interband absorption in noble metals, while for Al, Be, and the transition metals both models exhibit good agreement with the experimental data. A comparison with measurements on surface normal structures confirmed that the reflectance and the phase change on reflection from semiconductor-metal interfaces (including the case of metallic multilayers) can be accurately described by use of the proposed models for the optical functions of metallic films and the matrix method for multilayer calculations.
3,629 citations
TL;DR: A comparative study of various materials including metals, metal alloys and heavily doped semiconductors is presented in this article, where the performance of each material is evaluated based on quality factors defined for each class of plasmonic devices.
Abstract: Plasmonics is a research area merging the fields of optics and nanoelectronics by confining light with relatively large free-space wavelength to the nanometer scale - thereby enabling a family of novel devices. Current plasmonic devices at telecommunication and optical frequencies face significant challenges due to losses encountered in the constituent plasmonic materials. These large losses seriously limit the practicality of these metals for many novel applications. This paper provides an overview of alternative plasmonic materials along with motivation for each material choice and important aspects of fabrication. A comparative study of various materials including metals, metal alloys and heavily doped semiconductors is presented. The performance of each material is evaluated based on quality factors defined for each class of plasmonic devices. Most importantly, this paper outlines an approach for realizing optimal plasmonic material properties for specific frequencies and applications, thereby providing a reference for those searching for better plasmonic materials.
1,615 citations
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TL;DR: A comparative study of various materials including metals, metal alloys and heavily doped semiconductors is presented and an approach for realizing optimal plasmonic material properties for specific frequencies and applications is outlined.
Abstract: Plasmonics is a research area merging the fields of optics and nanoelectronics by confining light with relatively large free-space wavelength to the nanometer scale - thereby enabling a family of novel devices. Current plasmonic devices at telecommunication and optical frequencies face significant challenges due to losses encountered in the constituent plasmonic materials. These large losses seriously limit the practicality of these metals for many novel applications. This paper provides an overview of alternative plasmonic materials along with motivation for each material choice and important aspects of fabrication. A comparative study of various materials including metals, metal alloys and heavily doped semiconductors is presented. The performance of each material is evaluated based on quality factors defined for each class of plasmonic devices. Most importantly, this paper outlines an approach for realizing optimal plasmonic material properties for specific frequencies and applications, thereby providing a reference for those searching for better plasmonic materials.
1,557 citations
TL;DR: In this article, the ultraviolet-visible absorption spectra of colloidal particles of 52 of the metallic elements, calculated from the optical constants of the metals by means of Mie theory, are given.
Abstract: The ultraviolet–visible absorption spectra are given for 10 nm diameter colloidal particles of 52 of the metallic elements, calculated from the optical constants of the metals by means of Mie theory. For most of the elements the spectra cover the range 200–900 nm. Well resolved absorption bands are observed for colloidal Sc, Ti, V, Y, Cd, Eu, Yb, Hg and Th as well as for colloids of Cu, Ag, Au and the s-block metals. However, for the majority of the colloidal metallic elements in this size range there is only a continuous absorption in the visible range, rising to broad and poorly resolved absorption bands in the ultraviolet near 200 nm. The difference in the way that the spectra of colloidal particles of different metals change when the particle shape is varied from spherical to spheroidal is investigated systematically in the dipole approximation. This is achieved by means of contour plots of the absorbance cross-section for the particles vs. the real and imaginary parts of the dielectric function for the metals, and this method of investigation is extended also to hollow spherical particles. The results suggest that Ca, Sr, Ba, Eu, Yb, Th and possibly Sc, Ti, V and Y may merit experimental investigation as new metals for exhibiting surface-enhanced Raman scattering.
1,501 citations
1,222 citations