This shadow was visible to the naked eye, followed the contours of the laser beam, and moved with its source. The key to this effect lies in ruby's unusual optical properties.

BluGlass, a Sydney, Australia-based developer of visible wavelength lasers for the quantum, defence, and biotech markets, has demonstrated what it calls “world-record performance” of its single-mode ...

image: a−d, spot patterns simulated by the mathematical model b, photographs of the spot patterns obtained using a visible laser.. view more . Credit: by Yufei Ma, Yahui Liu, Ying He, Shunda ...