Science Daily August 12, 2022 Researchers in the UK modeled propagation of far-red-detuned optical vortex beams through a Bose-Einstein condensate using nonlinear Schrödinger and Gross-Pitaevskii equations. They showed the formation of coupled light-atomic solitons that rotate azimuthally before moving off tangentially, carrying angular momentum. The number, and velocity, of solitons, depends on the orbital angular momentum of the optical field. Using a Bessel-Gauss beam increases radial confinement so that solitons can rotate with fixed azimuthal velocity. According to the researchers the model provides a highly controllable method of channeling a BEC and atomic transport…read more. TECHNICAL ARTICLE
Category Archives: Light
The handedness of light holds the key to better optical control
Phys.org July 18, 2022 Current optical modulators used to manipulate the properties of a beam of light mainly use electrical or acoustic effects. These technologies can control the properties of light at nanosecond speeds. Researchers in Finland have developed an all-optical modulator technique which uses a coherent optical process. It can work at femtosecond speeds. They experimentally validated the concept in monolayer materials (MoS2) with modulation depth approaching ~100%, ultra-fast modulation speed (<~130 fs), and wavelength-independence features. The power and polarization of the incident optical beams can be used to tune the output chirality and modulation performance. According to the researchers […]
Direct generation of complex structured light
Phys.org March 18, 2022 An international team of researchers (China, USA – Arizona State University) generated structured transverse mode locking (TML) beams and second harmonic generation (SHG) beams by a sandwich-like microchip laser cavity that was passively Q-switched. They observed many rare SHG far-field beam patterns and their experiments showed good agreement with the simulations. It showed that parametric variation for the TML modes greatly changes the far-field beam patterns of the SHG beam. Generated SHG beam patterns vary with the propagation, and then they remain stable into the far field. The SHG beam patterns were observed to have more […]
Discovery of ‘split’ photon provides a new way to see light
Nanowerk December 13, 2021 Bosons, such as photons, tend to bunch together unlike fermions. Thus it was natural for researchers to assume that splitting bosons would be an insurmountable task. According to a team of researchers in the US (Dartmouth College, SUNY Polytechnic Institute) the interplay between dynamical metastability and nontrivial bulk topology makes possible emergence of Majorana bosons. This leads to a distinctive form of topological metastability, whereby a conserved Majorana boson localized on one edge is paired, in general, with a symmetry generator localized on the opposite edge. They argue that Majorana bosons are robust against disorder and […]
‘Liquid’ light shows social behaviour
Phys.org October 7, 2021 Researchers in the Netherlands investigated the Bose-Einstein condensation of a photonic Bose gas in an environment with controlled dissipation and feedback. They created a micro-size mirror with channels in which photons flow like a liquid. They showed that by adjusting their frequency Bose-Einstein condensates naturally try to avoid particle loss and destructive interference in their environment. Their experiments revealed physical mechanisms involved in the formation of a Bose-Einstein condensate, which typically remain hidden when the system is close to thermal equilibrium. They demonstrated the effect even at room temperature. Their measurements offer a highly systematic picture […]
Microscopic metavehicles powered by nothing but light
Science Daily September 28, 2021 Optical tweezers were developed using a highly focused laser beam to control and maneuver tiny particles. An international team of researchers (Sweden, Russia) has shown that even unfocused light can be used to maneuver microscopic particles in a controlled manner by developing “metavehicle” consisting of a tiny particle coated with metasurface. They used the forces resulting from the light’s change in momentum control the meta-surface. By placing the metavehicle at on the bottom of the water dish, they used loosely focused laser to direct a plane wave of light onto them moving the metavehicle in […]
Physicists mix classical light with half a photon on a qubit
Phys.org August 31, 2021 An international team of researcher (Russia, UK) theoretically considered wave mixing under the irradiation of a single qubit by two photon fields. The first signal was a classical monochromatic drive, while the second one was a nonclassical light. They addressed two examples of a nonclassical light: (i) a broadband squeezed light and (ii) a periodically excited quantum superposition of Fock states with 0 and 1 photons. The mixing of classical and nonclassical photon fields gives rise to side peaks due to the elastic multiphoton scattering. They showed that a side peaks structure is distinct from the […]