Science Alert  July 15, 2023 Scientists experimenting with some of the most fundamental laws of physics have found more evidence of photonic time crystals (PTCs): materials in which the refractive index oscillates very quickly. An international team of researchers (Israel, USA – University of Perdue) trained lasers on two transparent conducting oxides and used the lasers to rapidly change the refractive index for periods less than 10 femtoseconds. They observed significant shifts in the light frequency and in the light relaxation time depending on the thickness of the material and the speed with which the refractive index was altered. Increasing […]