Einstein’s general theory of relativity is one of the cornerstones in modern physics. It holds the best understanding of gravity so far, explaining that the nature of universal gravitation originates from matter-energy, resulting in curved spacetime. To date, general relativity (GR) has passed all the experimental tests with flying colors, such as the precession of Mercury , gravitational redshift , the observations of solar-mass pulsars in binary systems , and the gravitational waves from several stellar mass, black hole candidate in-spirals . Recently, the report of first detection of the Schwarzschild precession in S2’s orbit around the nearest massive black hole (candidate) in the Galaxy Center has received attention, being more prominent evidence of GR . In optics, in analogy to the equality between matter-energy and curved spacetime, macroscopic Maxwell’s equations in complex inhomogeneous media can be mapped into free-space Maxwell’s equations of an arbitrary spacetime metric [6–10], leading to lots of transformation optical applications like invisibility cloaks [11–17], field rotators [18,19], and illusion devices . Moreover, despite the functionality of controlling the flow of light, this analogy has also been utilized to mimic some exciting gravitational effects related to GR in return, for instance, black holes [21–27], Einstein’s ring , de Sitter space [29,30], and cosmic strings [31,32].
Set citation alerts for the article
Please enter your email address