Planar refraction and lensing of highly confined polaritons in anisotropic media

Refraction between isotropic media is characterized by light bending towards the normal to the boundary when passing from a low- to a high-refractive-index medium. However, refraction between anisotropic media is a more exotic phenomenon which remains barely investigated, particularly at the nanoscale. Here, we visualize and comprehensively study the general case of refraction of electromagnetic waves between two strongly anisotropic (hyperbolic) media, and we do it with the use of nanoscale-confined polaritons in a natural medium: α-MoO3. The refracted polaritons exhibit non-intuitive directions of propagation as they traverse planar nanoprisms, enabling to unveil an exotic optical effect: bending-free refraction. Furthermore, we develop an in-plane refractive hyperlens, yielding foci as small as λp/6, being λp the polariton wavelength (λ0/50 compared to the wavelength of free-space light). Our results set the grounds for planar nano-optics in strongly anisotropic media, with potential for effective control of the flow of energy at the nanoscale.

Traveling towards fame: Albert Einstein and the Eddington eclipse expedition to Príncipe and Sobral in 1919

Albert Einstein abruptly rose to worldwide fame in November 1919, after Arthur Eddington announced the successful measurement of the gravitational light bending predicted by Einstein’s general theory of relativity. The measurement had been performed by an expedition towards two remote Portuguese-speaking destinations, the island of Príncipe in equatorial Africa and Sobral in northern Brazil, where the total solar eclipse of May 29, 1919 was visible and allowed to measure the position of stars close to the Sun, revealing the sought-after effect. This journey was the beginning of a story that still goes on today.

Weak deflection angle of black-bounce traversable wormholes usingGauss–Bonnet theorem in the dark matter medium

In this paper, we first use the optical metrics of black-bounce traversable wormholes to calculate the Gaussiancurvature. Then we use the Gauss–Bonnet theorem to obtain the weak deflection angle of light from the black-bouncetraversable wormholes. We investigate the effect of dark matter medium on weak deflection angle using the Gauss–Bonnet theorem. We show how weak deflection angle of wormhole is affected by the bounce parametera. Using theGauss–Bonnet theorem for calculating weak deflection angle shows us that light bending can be thought as a global andtopological effect.

Weak Deflection Angle of Black-bounce Traversable Wormholes Using Gauss-Bonnet Theorem in the Dark Matter Medium

In this paper, first we use the optical metrics of black-bounce traversable wormholes to calculate the Gaussian curvature. Then we use the Gauss-Bonnet theorem to obtain the weak deflection angle of light from the black-bounce traversable wormholes. Then we investigate the effect of dark matter medium on weak deflection angle using the Gauss-Bonnet theorem. We show how weak deflection angle of wormhole is affected by the bounce parameter $a$. Using the Gauss-bonnet theorem for calculating weak deflection angle shows us that light bending can be thought as a global and topological effect.