A method of cosmetically treating skin tissue includes the steps of: providing a light source to direct one or more light energy beams to the skin tissue； providing a prism and interposing the prism between the light source and the skin tissue； activating the light source. The one or more light energy beams passing through the prism converge and are focused to one or more focal points at or near the skin tissue surface； and then each of the one or more light energy beams each diverge after passing through the one or more focal points to each create a plurality of microchannels in the skin tissue.
