Excalibur

A celestial sword, constructed by the world from the collective wishes of mankind and fueled through a conversion of Mana into photoelectric energy. The area of expulsion appears as a colossal beacon of incandescence, though the vast majority of light is concentrated at the vertex of initial release. Kinetic entropy is intensified by the acceleration and convergence of momentum at this vertex, with only trace calidity in the dissipating tail. The concentric area of impact is broad enough to incinerate an entire military cohort. This Noble Phantasm is named after the legendary sword of King Arthur, bestowed onto the king by Lady of the Lake.

Additional source: Fate/Stay Night game translation v1.0a by Mirror Moon