The phase and the group velocity of light propagating in conventional optical media cannot exceed the speed of light in vacuum. However, in so-called epsilon-near-zero (ENZ) materials, light exhibits ...

It’s a snap-on interface for electric meters, dubbed so because its ... a Wemos-compatible development board with an ESP32 MCU, an optical interface board, and a few small parts like a ring ...

The nonlinear susceptibility is a measure of a material's nonlinear response to an applied electric field. It determines the strength of the nonlinear effects and is related to the crystal's symmetry ...