1. A noninvasive method for providing focused tissue stimulation to a human patient, comprising of performing a procedure to determine the location of target tissue at which a desired stimulation is to be performed; positioning a source of electromagnetic radiation at first focal point of an elliptically curved reflecting surface, placing both said reflecting surface and said first focal point outside of said patient body; positioning said target tissue to overlap with the second focal point of said elliptically curved reflecting surface; applying an electrical current signal to said source to generate radiation of electromagnetic radiation at one or more selected frequencies; and continuing said radiation of a predetermined treatment session duration to affect said tissue, wherein the tissue is brain tissue and said desired stimulation is brain waves amplitude enhancement, where said brain waves frequency is in the range of 0 to 20 Hz, and said radiation frequency is in the range of 0 to 20 Hz.