Phys.org February 7, 2023 Both real-world and experimentally simulated turbulence conditions have revealed that free-space structured light modes are perturbed by turbulence resulting in both amplitude and phase distortions, and consequently, much attention has focused on whether one mode type is more robust than another, but with inconclusive and contradictory results. Researchers in South Africa have shown complex forms of structured light that are invariant under propagation through the atmosphere: the true eigenmodes of atmospheric turbulence. They provided a theoretical procedure for obtaining these eigenmodes and confirmed their invariance both numerically and experimentally. According to the researchers although they have […]
Tag Archives: Light propagation
Researchers measure the binding state of light and matter for the first time
Phys.org August 1, 2022 Light-matter interaction is well understood on the single-atom level and routinely used to manipulate atomic gases. However, in denser ensembles, collective effects emerge that are caused by light-induced dipole-dipole interactions and multiple photon scattering. An international team of researchers (Austria, Germany) found a mechanical deformation of a cloud of ultracold 87Rb atoms due to the collective interplay of the atoms and a homogenous light field. The collective light scattering results in a self-confining potential which exhibits nonlocal properties, attractive for both red- and blue-detuned light fields and induces a remarkably strong force that depends on the […]
Smuggling light through opaque materials
Nanowerk October 5, 2021 Chalcogenide glasses have long been constrained to the near- and mid-infrared with respect to their applications in photonics because they strongly absorb wavelengths of light in the visible and ultraviolet parts of electromagnetic spectrum. An international team of researchers (USA – Duke University, US Naval Research Laboratory, industry, university of Pennsylvania, Aviation and Missile Center, Aviation and Missile Center, US Army, Italy) has experimentally demonstrated and reported near-infrared to ultraviolet frequency conversion in an As2S3-based metasurface, enabled by a phase locking mechanism between the pump and the inhomogeneous portion of the third harmonic signal. Due to […]
Researchers create new state of light
Phys.org February 25, 2020 Light rotates around a longitudinal axis parallel to the direction light travels. An international team of researchers (China, USA – University of Dayton) has demonstrated a three-dimensional wave packet that is a spatiotemporal (ST) optical vortex with a controllable purely transverse orbital angular momentum (OAM). The magnitude of the transverse OAM carried by the ST vortex is scalable to a larger value by simple adjustments. Since the ST vortex carries a controllable OAM uniquely in the transverse dimension, it has strong potential for novel applications that may not be possible otherwise. The scheme reported here can […]
Images: Decoding multiple frames from a single, scattered exposure
Science Daily September 27, 2018 The random process of scattering in turbid media produces scattered light that appears uninformative to the human eye, but a wealth of information is contained in the signal. Previous methods to recover the image from the ‘memory effects’ required that the object and/or scatterer be static during the measurement. Researchers at Duke University combined traditional memory effect imaging with coded-aperture-based computational imaging techniques, which enabled them to realize for the first time single-shot video of arbitrary dynamic scenes through opaque media. This has important implications for a wide range of real-world imaging scenarios in security, […]
Rotating resonator creates a one-way street for light
Physics World June 29, 2018 An international team of researchers (Israel, USA – University of Central Florida, University of Michigan, China, Japan) used a cylindrical, silica-glass resonator that is rotating on a turbine. An optical fibre is located 320 nm above the spinning resonator. Light travelling along the fibre interacting with the nearby resonator via the light’s short-range evanescent field perceives it to be less dense than light travelling in the opposite direction. This difference in apparent density results in different indices of refraction for light moving in opposite directions allowing the researchers to pass light of the same frequency […]