Laser beam can cast a shadow under certain conditions

In a new study, researchers used a ruby crystal and specific laser wavelengths to show that a laser beam can block light and cast a visible shadow through a nonlinear optical process. This occurs when light interacts with a material in an intensity-dependent way, influencing another optical field. Lead researcher Abrahao suggests that this discovery could have applications in optical switching, where one light controls another, and in technologies requiring precise light transmission control, such as high-power lasers.