Curved Spacetime Mimicked on a Chip: Scientific American

Curved Spacetime Mimicked on a Chip: Scientific American: Liu and his collaborators simulated the gravitational lensing of a star on an integrated photonic chip. A layer of clear plastic on the chip acted as a waveguide, confining light to the chip’s surface. To change the index of refraction of the plastic, the researchers had to vary the plastic’s thickness. They did so by heating the plastic and adding polystyrene microspheres before the plastic cooled. Because the plastic rose upwards around the microspheres on cooling, the thickness of the waveguide increased near these miniature balls. The varying index of refraction the team achieved happens to be very similar to the bending of space-time geometry around a massive star...

“This is indeed the first time an exact solution of Einstein's equations was mimicked” using an optical model, says Leonhardt.