Phys.org  October 19, 2024 Optical Stark effect is an example of using Floquet engineering for optical trapping of atoms and breaking time-reversal symmetry in solids. However, floquet engineering typically requires high field intensities obtained in ultrafast pulses, severely limiting its use. An international team of researchers (USA – University of Michigan, Japan, Taiwan) demonstrated using cavity engineering of the vacuum modes to achieve Floquet effects at an extremely low fluence of 450 photons/μm2. At higher fluences, the cavity-enhanced Floquet effects led to 50 meV spin and valley splitting of WSe2 excitons, corresponding to an enormous time-reversal breaking. They demonstrated an […]