A method for generating extreme ultraviolet (EUV) light that includes the steps of supplying a droplet of a target material into a chamber, diffusing the droplet by irradiating the droplet by a pre-pulse laser beam to form a diffused target, and generating a plasma by irradiating the diffused target by a main pulse laser beam wherein the plasma emits extreme ultraviolet light. The main pulse laser beam has a cross-sectional shape that is substantially coincident with a shape of the diffused target at the irradiation point.