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Special issue on aluminium plasmonics

Plasmonics is a rapidly growing field that takes advantage of the intense and confined electromagnetic fields that appear near metallic nanostructures illuminated at frequencies near their surface plasmon resonances [1]. As plasmonics continues to develop, it faces the need to find new materials supporting well-defined surface plasmon resonances in different frequency ranges [2]. In the visible and near-infrared ranges the noble metals, most typically gold and silver, exhibit relatively low losses. This is why they are quite ubiquitous in plasmonics literature. However it is somewhat ironic to see that a non-noble metal, aluminium, the metal upon which surface plasmons where first evidenced in the 1950s [3], is now reappearing after fifty years of near oblivion as one of the ‘hottest’ materials for plasmonics. Several reasons explain the return of aluminium to the centre stage. First, aluminium exhibits good plasmonic properties in the ultraviolet and deep ultraviolet—a spectral range where gold and silver no longer behave as metals. Second, aluminium is cheap and widely available (Al is the third most abundant element in the earth’s crust), criteria of paramount importance when discussing industry-related applications. It is furthermore compatible with complementary metal–oxide–semiconductor (CMOS) technology. This is why an ever-increasing number of papers report new advances on aluminium plasmonics. This renewed interest in aluminium was even called ‘the aluminium rush’ [4]. Aluminium plasmonics-based devices are now being demonstrated, such as ultraviolet plasmon nanolasers [5] or CMOS-compatible photodetectors [6], to name only a few (see our review [7] for further detail). We hope the nine papers from this special issue will give the reader an overview of this new field. The issue opens with two review papers, one general review and one review on the fabrication techniques applied to aluminium plasmonics [7, 8]. Seven original research papers follow. These papers cover the optical [9, 10] and electronic [11] properties of aluminium nanostructures, applications of aluminium plasmonics for photocatalysis [12], fluorescence enhancement [13] and the nanofocusing of ultraviolet light [14] and finally the fabrication of nanostructures resonating in the ultraviolet [15].