nonlinear optics

Researchers have demonstrated that a laser beam can cast a visible shadow, much like a material object. This effect relies on nonlinear optics and the unique properties of ruby crystals, which increase absorption under specific conditions. The shadow mimics those of physical objects, meeting standard criteria such as following surface contours and shape. This groundbreaking discovery redefines our understanding of shadows and light interactions, with potential applications in optical switching, imaging, and controlled light transmission. The findings could pave the way for novel technologies in photonics and everyday light manipulation.