Figure 1

Electron-beam-driven collective metamaterial light source concept. (a) Highly localized electron-beam excitation at the center of a metamaterial array leads, via the strong coupling among metamolecules, to the collective oscillation of many cells and thereby the emission of a free-space light beam. (b)–(d) Numerically calculated amplitude profiles of the three strongest collective eigenmodes $M_{pq}$ of a center-driven finite ($32\times 32$ cell) array. A low-divergence free-space wave is launched in the surface normal direction by the dominant $M_{11}$ mode.Reuse & Permissions

Figure 2

Electron-induced emission vs optical absorption in a plasmonic metamaterial. (a) Electron-beam-induced metamaterial light emission spectra for arrays with different metamolecule cell sizes (as labeled). (b) Corresponding optical absorption spectra (derived from microspectrophotometric measurements of normal incidence transmission and reflection). The inset to (b) shows a schematic of the asymmetric split ring metamolecule.Reuse & Permissions

Figure 3

Directional resonant light emission from a plasmonic metamaterial. (a) Experimental configuration for angle-resolved detection of electron-induced light emission. (b),(c) Angular intensity distributions of total electron-induced light emission from a metamaterial array with a 220 nm unit cell, integrated over all wavelengths from 400 to 1100 nm (b), and the metamaterial-specific component of this spectrally integrated emission [(c), background contribution from unstructured gold removed]. (d) Emission intensity as a function of polar angle (integrated over azimuth angle) for the two cases shown in (b) and (c).Reuse & Permissions

Figure 4

Spectral collapse of metamaterial emission. (a) Electron-induced metamaterial light emission spectra for a sequence of beam injection positions at intervals of 400 nm along a line perpendicular to the boundary of the metamaterial array (each averaged over ten injection points spaced along lines parallel to the boundary as indicated on the inset secondary electron image). (b) Intensity and half-maximum width of the 633 nm emission line as functions of the electron beam injection coordinate and the number of metamolecules within the $1/e^2$ source radius of the injection point. (c) 633 nm emission intensity at as a function of electron beam current.Reuse & Permissions