Engineering of low-loss metal for nanoplasmonic and metamaterials applications

Abstract

We have shown that alloying a noble metal (gold) with another metal (cadmium), which can contribute two electrons per atom to a free electron gas, can significantly improve the metal's optical properties in certain wavelength ranges and make them worse in the other parts of the spectrum. In particular, in the gold-cadmium alloy we have demonstrated a significant expansion of the spectral range of metallic reflectance to shorter wavelengths. The experimental results and the predictions of the first principles theory demonstrate an opportunity for the improvement and optimization of low-loss metals for nanoplasmonic and metamaterials applications.

Aberration-Free Ultrathin Flat Lenses and Axicons at Telecom Wavelengths Based on Plasmonic Metasurfaces

“…This is mainly due to the reflection inside the substrate and the optical losses, which are estimated using FDTD simulations to be approximately 40% and 20%, respectively. The optical losses can be reduced using low--loss metals [31,32] or other plasmonic materials [33]. The efficiency can be further improved by using impedance matching techniques (e.g.…”

Plasmonic near-field transducer for heat-assisted magnetic recording

“…Additionally, a recent work [81] demonstrated the absorption efficiency of particles as the critical FOM for local heating applications. Recently, there is a significant interest in searching for alternative low-loss plasmonic materials [76,[82][83][84][85][86], and applying these materials in SP, LSP, transformation optics, and metamaterials. Some of these alternative plasmonic materials for visible and near infrared frequencies may offer a possibility of achieving high performance for NFT devices.…”

“…Some of these alternative plasmonic materials for visible and near infrared frequencies may offer a possibility of achieving high performance for NFT devices. As discussed in [84], the reported alternative plasmonic materials can be loosely categorized as metallic alloys [78,79,82], semiconductor-based [76], ceramic materials [85], 2D materials such as grapheme [76,86] and organic materials [87]. Among these materials, metallic alloys, semiconductor-based transparent conducting oxides (TCOs), and transition-metal nitrides [84,86,88] can be promising for HAMR application near a wavelength of 800 nm.…”

“…Alloying metals with different proportions of each element will create a unique band structure that shifts the interband transition to a less critical spectral range. As shown in Figure 10A, the original bands I (centered around 667 nm) and II (centered around 333 nm) of gold can overlap at about 500 nm in the alloy, leaving other part of spectrum less lossy [82]. For TCOs and metal-nitrides, optical properties of thin films were characterized and fitted with a Drude+Lorentz oscillator model [84].…”

Design and implementation of plasmonic metamaterials and devices

“…low loss metals-has been pointed out [35], and metal alloys have been proposed to that end 134 CHAPTER 5. PLASMONIC INTERFERENCE PHENOMENA [265]. Another approach is to compensate the plasmonic losses with gain in active media [266,267].…”