Magnesium as Novel Material for Active Plasmonics in the Visible Wavelength Range

Abstract

Investigating new materials plays an important role for advancing the field of nanoplasmonics. In this work, we fabricate nanodisks from magnesium and demonstrate tuning of their plasmon resonance throughout the whole visible wavelength range by changing the disk diameter. Furthermore, we employ a catalytic palladium cap layer to transform the metallic Mg particles into dielectric MgH2 particles when exposed to hydrogen gas. We prove that this transition can be reversed in the presence of oxygen. This yields plasmonic nanostructures with an extinction spectrum that can be repeatedly switched on or off or kept at any intermediate state, offering new perspectives for active plasmonic metamaterials.

How an oxide shell affects the ultraviolet plasmonic behavior of Ga, Mg, and Al nanostructures

“…In this way, with the former we mimic experimental conditions for colloidal chemistry and with the latter, the typical experimental conditions for metallic nanostructures on substrates made of either Ga or Mg [11][12][13][14]. Although the typical Al NP geometry is usually not hemispherical, we use this geometry to facilitate comparison.…”

“…In previous studies, the plasmonic performance of various metals in the UV has been analyzed. Among them, aluminum (Al) [3,[6][7][8][9][10], gallium (Ga) [7,[10][11][12][13], magnesium (Mg) [7,14], and rhodium (Rh) [15][16][17] were identified as particularly promising candidates for UV plasmonics, with properties approaching those of silver (Ag) and gold (Au) widely used for plasmonic applications in the VIS-NIR [10,18]. However, the efficiencies of these metals depends sensitively on the surrounding dielectric environment, and all of them, except Au and Rh, form native oxides that wrap the NP with a shell, whose thickness depends on both the metal and the environmental exposure conditions (temperature and pressure).…”

“…Consequently, it is essential to understand the effect of oxidation on their UV plasmonic response [7,9,19]. Also, very recently it was shown that, since oxidation is a means to grow a dielectric shell, its control may be used to tune the plasmonic resonance of NPs [14].…”

Nonlinear optical response of Mg/MgO structures prepared by laser ablation method

“…Furthermore, the real and imaginary parts of χ (3) are listed in Table 1. The imaginary part of χ (3) is related to β as [23]:…”

“…As reported by Sterl et al, magnesium nanoparticles exhibit a pronounced plasmonic response at throughout the whole visible wavelength range. Therefore, it can be an ideal alternative to established materials for UV plasmonics such as aluminum [3]. Magnesium is an excellent candidate for weight critical structural applications for its impressive low mass density.…”