Surface-coupling of Cerenkov radiation from a modified metallic metamaterial slab via Brillouin-band folding

Abstract

Metallic metamaterials with positive dielectric responses are promising as an alternative to dielectrics for the generation of Cerenkov radiation [J.-K. So et al., Appl. Phys. Lett. 97(15), 151107 (2010)]. We propose here by theoretical analysis a mechanism to couple out Cerenkov radiation from the slab surfaces in the transverse direction. The proposed method based on Brillouin-zone folding is to periodically modify the thickness of the metamaterial slab in the axial direction. Moreover, the intensity of the surface-coupled radiation by this mechanism shows an order-of-magnitude enhancement compared to that of ordinary Smith-Purcell radiation.

High‐Q Metallic Fano Metamaterial for Highly Efficient Cerenkov Lasing

“…Since a single group of electrons does not strongly enhance the Fano resonances in the metamaterials, CL and SPR are not enhanced. This explains why a recent similar work did not observe the existence and enhancement of Fano resonances for CL using the description with band‐folding effect (see Note S11 of the Supporting Information) . In terms of enhancement, a continuous electron beam is employed to enhance the trapped modes via a distributed‐feedback process for electron bunching, as shown in Note S12 of the Supporting Information .…”

“…These limitations restrict the upper and lower size and performance boundaries in vital applications. Nowadays, metallic metamaterial devices have been proposed, which overcome the limitations of conventional Cerenkov devices to realize reversed CR from the negative‐refractive index, the ultralow threshold of kinetic energy in hyperbolic metamaterials, and various metallic metamaterials comprised of subwavelength slits . However, the realization of a high quality factor (Q) is still an outstanding roadblock for practical Cerenkov devices.…”

Chiral Plasmons Enable Coherent Vortex Smith–Purcell Radiation

“…To bridge this mismatch, the Brillouin folding is introduced by modulating the depth of slots, where the structural parameters are set as d = 0.10 mm, L = 0.20 mm, a = 0.05 mm, R 1 = 0.35 mm, R 2 = 0.20 mm, and R 3 = 0.18 mm. [ 39 ] Similarly, the dispersion and field distributions of chiral SSPs of the depth‐modulated grating are calculated as shown in Figure 2c,d. Compared with the uniform one, the dispersion of the modulated grating is evolved by splitting the band twice at normalized k z = 0.5 and 1.5.…”

Utilizing the power of Cerenkov light with nanotechnology

“…Building on the metal slit design, an additional periodicity was introduced to the metamaterial (Fig. 7d–e), which revealed a magnitude increase in CL intensity of several orders 81 . Through deliberate periodic design, metamaterials can disobey CL generation requirements previously thought as fundamental phenomena properties.…”