Mitigating the Loss in Plasmonics and Metamaterials
Technical Report,28 Sep 2015,27 Jun 2016
Johns Hopkins University Baltimore United States
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Current materials of choice for plasmonics and metamaterials P and M are mostly metals, but also highly doped semiconductors, oxides and nitrides. The common feature of all these materials is high loss determined by absorption in which photon or surface plasmon gets absorbed and its energy is transferred to electron-hole pair. While there are many extrinsic factors that may increase or decrease the absorption strength defects, roughness, strength of electron-phonon coupling etc., fundamentally the absorption in the materials with large density of free carriers is high because of the large density of final states for the absorption. In the course of 9 month of work we have investigated various means of loss mitigation using alternative materials , such as heavily doped semiconductors, oxides and phononic materials. Despite lower material losses the polaritonic modes in these materials turned outto be just as lossy if not lossier than in the metals which we have attributed to the lower plasma frequency ion the alternative materials. The one and only way to have material with negative dielectric constant and low absorption is to synthesize a material in which the absorption would be forbidden by the energy conservation. We have identified two dimensional layered materials as potential candidates and approached a research group at DTU Denmark whose density functional calculations confirmed our prediction.
- Miscellaneous Materials