Phys.org November 14, 2024 An international team of researchers (Canada, USA – Brookhaven National Laboratory, University of Wisconsin-Madison, University of Rochester) demonstrated a laser beam acting like an object — the beam casts a shadow upon a surface when the beam is illuminated by another light source. They observed a regular shadow that could be seen by the naked eye, it followed the contours of the surface it fell on, and it followed the position and shape of the object (the laser beam). They used a nonlinear optical process involving four atomic levels of ruby. They were able to control […]
Tag Archives: Imaging
Janus-like metasurface technology shows different optical responses according to the direction of light
Phys.org October 15, 2024 Janus metasurfaces have the ability to control light asymmetrically at the pixel level within thin films. However, previous demonstrations are restricted to the partial control of asymmetric transmission for a limited set of input polarizations, focusing primarily on scalar functionalities. Researchers in the Republic of South Korea developed optical bi-layer metasurfaces that achieve a fully generalized form of asymmetric transmission for any input polarization. The theoretical model revealed a fundamental correlation between the polarization-direction channels of opposing sides. They partitioned the transmission space to realize four distinct vector functionalities within the target volume. As a proof […]
Entangled photon pairs enable hidden image encoding
Phys.org September 4, 2024 Photon-pair correlations in spontaneous parametric down-conversion are ubiquitous in quantum photonics. The ability to engineer their properties for optimizing a specific task is essential, but often challenging in practice. Researchers in France demonstrated the shaping of spatial correlations between entangled photons in the form of arbitrary amplitude and phase objects. By doing this, they encoded image information within the pair correlations, making it undetectable by conventional intensity measurements. It enabled the transmission of complex, high-dimensional information using quantum correlations of photons, which could be useful for developing quantum communication and imaging protocols… read more. TECHNICAL ARTICLE