The interactions of light and
matter with
spacetime, as predicted by
general relativity, can be studied using the new type of
artificial optical materials that feature extraordinary abilities to bend light (which is actually electromagnetic radiation). This research creates a link between the newly emerging field of artificial
optical metamaterials to that of
celestial mechanics, thus opening a new possibility to investigate
astronomical phenomena in a laboratory setting. The recently introduced, new class, of specially designed optical media can mimic the
periodic,
quasi-periodic and
chaotic motions observed in
celestial objects that have been subjected to
gravitational fields. If a metamaterial could be produced that did not have high intrinsic loss and a narrow
frequency range of operation then it could be employed as a type of
media to simulate light motion in a curved spacetime
vacuum. Such a proposal is brought forward, and metamaterials become prospective media in this type of study. The classical optical-mechanical analogy renders the possibility for the study of light propagation in
homogeneous media as an accurate analogy to the motion of massive bodies, and light, in gravitational potentials. A direct mapping of the celestial phenomena is accomplished by observing
photon motion in a controlled laboratory environment. The materials could facilitate periodic, quasi-periodic and chaotic light motion inherent to celestial objects subjected to complex gravitational fields. Twisting the optical metamaterial effects its "space" into new coordinates. The light that travels in real space will be curved in the twisted space, as applied in transformational optics. This effect is analogous to starlight when it moves through a closer
gravitational field and experiences curved spacetime or a
gravitational lensing effect. This analogue between classic
electromagnetism and general relativity, shows the potential of optical metamaterials to study relativity phenomena such as the gravitational lens. The study also points toward the design of
novel optical cavities and
photon traps for application in microscopic devices and lasers systems. The first experimental demonstration of electromagnetic black hole at
microwave frequencies occurred in October 2009. The proposed black hole was composed of non-resonant, and resonant, metamaterial structures, which can absorb electromagnetic waves efficiently coming from all directions due to the local control of electromagnetic fields. It was constructed of a thin
cylinder at 21.6 centimeters in
diameter comprising 60 concentric rings of
metamaterials. This structure created a gradient
index of refraction, necessary for bending light in this way. However, it was characterized as being artificially inferior substitute for a real black hole. The characterization was justified by an absorption of only 80% in the microwave range, and that it has no internal
source of energy. It is singularly a light absorber. The light absorption capability could be beneficial if it could be adapted to technologies such as solar cells. However, the device is limited to the microwave range. Also in 2009, transformation optics were employed to mimic a black hole of
Schwarzschild form. Similar properties of
photon sphere were also found numerically for the metamaterial black hole. Several reduced versions of the black hole systems were proposed for easier implementations. MIT computer simulations by Fung along with lab experiments are designing a metamaterial with a multilayer sawtooth structure that slows and absorbs light over a wide range of wavelength frequencies, and at a wide range of incident angles, at 95% efficiency. This has an extremely wide window for colors of light.
Multi-dimensional universe Engineering optical space with metamaterials could be useful to reproduce an accurate laboratory model of the physical multiverse. "''This 'metamaterial landscape' may include regions in which one or two spatial dimensions are compactified.''" Metamaterial models appear to be useful for non-trivial models such as 3D de Sitter space with one compactified dimension, 2D de Sitter space with two compactified dimensions, 4D de Sitter dS4, and anti-de Sitter AdS4 spaces. ==Gradient index lensing==