"Novel silicon etching technique crafts 3-D gradient refractive index micro-optics." ScienceDaily. www.sciencedaily.com / releases / 2016 / 11 / 161129153525.htm (accessed August 31, 2025).

Refractive index - the ratio of the speed of electromagnetic radiation in a medium to its speed in a vacuum - can be modulated fast enough to generate photonic time crystals (PTCs) in the near-visible ...

Physicists at Harvard University in the US have built a silicon waveguide that exhibits a refractive index of, or close to, zero when operating at near-infrared telecom wavelengths. The waveguide can ...

Physicists in the US have demonstrated negative refraction at optical wavelengths for the first time. Vladimir Shalaev and colleagues at Purdue University obtained the result in a material consisting ...

Researchers at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) say they have made it easier to manipulate light at the nanoscale. They have developed the first on-chip ...

"The key is that the optical properties are a function of the etch current," Braun said. "If you change the etch current, you change the refractive index. We also think that the fact that we can ...

PTCs, materials in which refractive index rises and falls rapidly in time, are the temporal equivalent of photonic crystals in which the refractive index oscillates periodically in space causing, for ...