Phys.org May 10, 2022 An international team of researchers (France, Germany) built a on-chip circuit which is a simple battery-biased superconducting tunnel junction in series with a microwave resonator. At discrete values of the battery voltage, a dc current flows through the circuit, with the emission of several photons at the resonator frequency for each superconducting pair of electrons that tunnels across the junction. They measured the total microwave power emitted and characterized the granularity of the emission both of which were good agreement with a simple theoretical model. In particular, at a small transparency of the tunnel junction, they […]
Tag Archives: Photon generation
Twistoptics: A new way to control optical nonlinearity
Science Daily March 4, 2021 A hot topic in the field of 2D materials has been exploring how twisting can change the electronic properties of the layered system. van der Waals (vdW) heterostructures feature layers that can be stacked at arbitrary angles, giving complete control over the presence or lack of inversion symmetry at a crystal interface. An international team of researchers (USA – Columbia University, industry, Germany, Japan) demonstrated highly tunable second harmonic generation (SHG) using bulk hexagonal boron nitride crystals and introduced the term twistoptics to describe studies of optical properties in twistable vdW systems. By suppressing residual […]
An electrical trigger fires single, identical photons
Phys.org October 8, 2020 An international team of researchers (USA – Lawrence Berkeley National Laboratory, Montana State University, Spain) has demonstrated electrically stimulated photon emission from individual atomic defects in monolayer WS2 and directly correlated the emission with the local atomic and electronic structure. Radiative transitions are locally excited by sequential inelastic electron tunneling from a metallic tip into selected discrete defect states in the WS2 bandgap. Coupling to the optical far field is mediated by tip plasmons, which transduce the excess energy into a single photon. The applied tip-sample voltage determines the transition energy. Inelastic charge carrier injection into […]