Plasmonic material

Gao H, Henzie J, Lee MH, Odom TW (2008) Screening plasmonic materials using pyramidal gratings. Proc Natl Acad Sci 105 20146... 

In order to excite SPP in a metallic tip, the metal is required to have an optical property that has a negative real and minimal imaginary part in the dielectric function at the excitation wavelength [98] as discussed in Sect. 4.2. As a plasmonic material in the UV region, aluminum can be used instead of silver and gold. The dielectric function of aluminum shows a reasonably small imaginary part while the real part keeps negative in the UV. 

Haes AJ et al (2005) Plasmonic materials for surface-enhanced sensing and spectroscopy. Mrs Bull 30(5) 368-375... 

P. West, S. Ishii, G.V. Naik, N.K. Emani, V.M. Shalaev, A. Boltasseva, Searching for better plasmonic materials. Laser Photonics Rev. 4, 795-808 (2010)... 

Besides the coinage metals, alkali metals (Li, Na, K, Rb, Cs) and A1 can also function as plasmonic materials, though it is very difficult to prepare stable nanostructured surfaces composed of these chemically active materials. Aluminum is a typical plasmonic material in the UV regime [39-41], while Ga, In, Pt and Rh, as well as their alloys and some complex materials (e.g., TiN), have also been explored as plasmonic materials [42]. 

The relative dielectric permittivity of plasmonic materials is negative below plasma frequency, and its dispersion is by Drude electron resonance model [298]... 

Elimination of absorption losses that are obviously undesired in photodetection is a field of active investigation, and different schemes were proposed for its avoidance [299]. One of the approaches is the use of alternative plasmonic materials [300] including graphene [301]. 

In other words, the effective dielectric permittivity of an EOT array has a form identical to that of plasmonic materials. At the same time, its plasma frequency and thus its operating range can be freely mned to the wavelength range of interest. Such surface waves actually mimic real SPP, so that one can fabricate an effective plasmonic material with a desired spectmm. Pendry denoted these surface waves as designer plasmons and they are also known as spoof plasmons. 

For other plasmonic materials the situation is similar to that of gold. In particular, both sources [37, 38] contain also data for silver and copper. Moreover, handbook by Palik [38] contains data for much more materials with a certain critique justifying the choice of particular values. Some of the known sources for many materials can be found in an online database [39]. 

Near-field microscopy is another usefiil application of DUV plasmonics. In this method, scanning probe microscopy was combined with optical microscopy. A nano-sized probe was coated with plasmonic materials to localize the incident light at its apex. The spectroscopic signal was obtained primarily at the probe apex, realizing a nanoscale imaging resolution. Recently, near-field DUV Raman scattering with an aluminum tip has been reported with an enhancement factor of 1,300... 

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