The present invention provides a precoding method for use in a wireless communications system. The method includes obtaining data from the touchpad. The detected radiation is produced by an array of radiation sources and is subsequently scattered, reflected, transmitted, or diffracted by the object under study and any features within the object under study. The pump unit and the operating unit are exclusively connected with each other in a wireless manner. The symmetric slots eliminate the need for a left side mechanism and a right side mechanism. The preferred embodiment utilizes an optically thin gold film anode, whereas the cathode was in the form of an optically thick aluminum film with patterned periodic subwavelength 2D hole array that showed anomalous transmission in the spectral range of the polymer photoluminescence band.