New pulse-width measurement for ultrashort laser pulse

A new pulse-width measuring method which is based on linear effect is presented. To the illumination of ultrashort laser pulse, the Talbot self-imaging effect of a grating is different from that of continuous wave. Thus by use of the difference, we can get the information of the pulse-width. The most noteworthy advantage of this method is that it is a linear method based on Fresnel diffraction approximation, thereby avoiding all the drawbacks relating to the previous nonlinear measuring methods by use of nonlinear effect. We bring forward three new techniques, the intensity integral technique, the intensity comparing ratio technique and the two-dimensional structure technique, to make this method applicable.