Renowned astrophysicist Rene A. Ong pays visit to the Joint Laboratory of Optics

Professor Rene A. Ong, a professor of astronomy and astrophysics at the Department of Physics and Astronomy at the University of California, Los Angeles, specializing in research in the field of astro-particle physics and high-energy astrophysics, visited the Joint Laboratory of Optics. Professor Ong currently serves as a co-spokesman for the CTA (Cherenkov Telescope Array) consortium, in which the Joint Laboratory of Optics is also involved.


Subtracting photons from photon pairs leads to increase of their nonclassicality

The group of quantum and nonlinear optics at the Joint Laboratory of Optics deals long-term with twin beams that became an important tool for quantum optics as they exhibit quantum correlations and entanglement. A. Aspect, J. Clauser, and A. Zeilinger were awarded 2022 Nobel prize for physics for experiments with entangled photons. Quantum correlations cause that the results of measurements of properties of paired photons are not independent but bound together at a distance with invisible ties unparalleled in classical physics. This is why we call the paired photons nonclassical light.


Speckle phenomenon helps to monitor plants stress

The Laser Speckle Laboratory in the Joint Laboratory of Optics has developed a non-invasive method for monitoring plants' responses to induced stress. Speckle is a phenomenon in which the matt (optically rough) surface of an object is illuminated by a coherent laser beam and the reflected light field shows a typical speckled pattern caused by interference of light reflected off different points of the object. The pattern of the reflected light field (speckle field) is sensitive to the object movements and deformations and thus allows the changes that the surface of the object undergoes to be precisely tracked. The speckle effect also arises when the laser beam passes through a translucent object.

The ATLAS experiment has observed the heaviest quark of the type t (top) in proton lead collisions

The LHC accelerator at CERN does not collide just protons, but also heavy nuclei, e.g. lead. In such collisions, conditions close to those as shortly after the Bing Bang can be simulated. In an early Universe the matter was in the state of a hot quark-gluon plasma and the top quark, the heaviest of all quarks, constitutes a new unique probe to study this form of matter. Owing to its large mass, it is born in processes leading to the quark-gluon plasma, rather than in the medium itself. Comparing processes known from proton-proton collisions to those with heavy ions, it is possible to study their production mechanism and use them as a probe testing the development of dense strongly interacting matter.