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 […]
Tag Archives: Photonic time crystals
Metamaterials: Time crystal gives light a boost
Nanowerk April 25, 2023 Photonic time crystals are artificial materials whose electromagnetic properties are uniform in space but periodically vary in time. The synthesis of these materials and experimental observation of their physics remains very challenging because of the stringent requirement for uniform modulation of material properties in volumetric samples. An international team of researchers (Finland, Germany, USA – Stanford University) has extended the concept of photonic time crystals to metasurfaces. They demonstrated that time-varying metasurfaces not only preserve key physical properties of volumetric photonic time crystals despite their simpler topology but also host common momentum bandgaps shared by both […]
Researchers discover new radiation effects in photonic time crystals
Phys.org April 26, 2023 Time metamaterials offer a great potential for wave manipulation. Researchers at the City University of New York explored the exotic wave dynamics of an anisotropic photonic time crystal (APTC) formed by an anisotropic medium whose optical properties are uniformly and periodically changed in time. Based on a temporal transfer matrix formalism, they showed that a stationary charge embedded in an APTC emits radiation, in contrast to the case of isotropic photonic time crystals, and its distribution in momentum space is controlled by the APTC band structure. According to the researchers their approach greatly extends the concept […]