In this photoacoustic imager, a light source driving portion is configured to stop power supply to a plurality of light-emitting semiconductor elements on the basis of that a forward voltage detection portion has detected forward voltage values of the plurality of light-emitting semiconductor elements corresponding to short circuiting of the light-emitting semiconductor elements. The first light source is configured for providing a first light beam. The structures formed from this method are preferably generated in fewer than four steps. The resistance devices are used to regulate current through the respective conductive finger during electroplating of the wafer.