Autocorrelation technique for measurement of width of optical short pulses based on polarization effects. A position of a user is determined. Furthermore, particle decontamination is performed in the presence of plasma, having a potential for helping to maximize a \u201cself bias\u201d voltage, under RF conditions, and is integrated into the vacuum process. The sheet maintains its shape by woven or non-woven cloth having a hole in which the integrated circuit is buried.