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 […]