Surface Dyakonov–Cherenkov radiation

Abstract

Recent advances in engineered material technologies (e.g., photonic crystals, metamaterials, plasmonics, etc.) provide valuable tools to control Cherenkov radiation. In all these approaches, however, the particle velocity is a key parameter to affect Cherenkov radiation in the designed material, while the influence of the particle trajectory is generally negligible. Here, we report on surface Dyakonov–Cherenkov radiation, i.e. the emission of directional Dyakonov surface waves from a swift charged particle moving atop a birefringent crystal. This new type of Cherenkov radiation is highly susceptible to both the particle velocity and trajectory, e.g. we observe a sharp radiation enhancement when the particle trajectory falls in the vicinity of a particular direction. Moreover, close to the Cherenkov threshold, such a radiation enhancement can be orders of magnitude higher than that obtained in traditional Cherenkov detectors. These distinct properties allow us to determine simultaneously the magnitude and direction of particle velocities on a compact platform. The surface Dyakonov–Cherenkov radiation studied in this work not only adds a new degree of freedom for particle identification, but also provides an all-dielectric route to construct compact Cherenkov detectors with enhanced sensitivity.

Free-electron-light interactions in nanophotonics

“…As with other effects in the grazing-angle interaction zone, one can predict which SPP modes are excited by an electron with velocity reduced β by identifying the intersection of the dispersion relation with the electron line 159 ω(k ) = vk . Analogues of this effect have been observed in systems supporting Dyakonov surface waves 163 and hyperbolic dispersion. 110…”

From Dyakonov-Cherenkov radiation to Dyakonov surface optics

“…Now a team led by Prof. Yu Luo from Singapore considers a situation when the particle emits surface electromagnetic waves at the interface between an isotropic and a uniaxial-birefringent medium (Dyakonov surface waves 6 ). The resulting Dyakonov-Cherenkov radiation is shown to be highly sensitive to both the value and the direction of the particle velocity 7 . In particular, it is shown that close to the Cherenkov threshold, the radiation intensity can be several orders of magnitude greater than that in traditional Cherenkov detectors.…”

Broadband Enhancement of Cherenkov Radiation Using Dispersionless Plasmons

“…In the structural schematic shown in Figure 1a, the current density of a free electron $$J\ ( {\bar{r},t} ) = \hat{z}\ {v}_{\rm{e}}e\delta ( x )\delta ( {y - {y}_0} )\delta ( {z - {v}_{\rm{e}}t} )$$ in the free space (with ε r1 = 1) induces a vector potential as [ 60,9 ] $$\begin{equation}{\bar{\phi }}_0 = \hat{z}\ \mathop \smallint \limits_{ - \infty }^{ + \infty } {\rm{d}}{k}_x\frac{{{\rm{i}}e}}{{8{\pi }^2{k}_{y1}}}{e}^{{\rm{i}}{k}_xx + {\rm{i}}{k}_y\left| {y - {y}_0} \right| + {\rm{i}}\frac{\omega }{{{v}_{\rm{e}}}}z}\end{equation}$$where e is the elementary charge. The vector potential enables to determine the source field of the free electron as $$\begin{equation} \left\{ \def\eqcellsep{&}\begin{array}{l}\bar{E}\left(\bar{r},\omega \right)=\frac{\mathrm{i}}{\omega {\varepsilon}_{0}}\nabla \ensuremath{\times{}}\nabla \ensuremath{\times{}}{\bar{\phi}}_{0}\\ \bar{H}\left(\bar{r},\omega \right)=\nabla \ensuremath{\times{}}{\bar{\phi}}_{0}\end{array} \right.$$…”