Experimental investigation of pulse propagation through RMS width and pulse quality factor

Summary form only given. By using the analogy between paraxial free space diffraction and second-order dispersion, it has recently been proposed that the propagation of short laser pulses in dispersive materials could be characterized by the same tools that are used for beam propagation. It was shown that the tern poral duration and spectral width of short laser pulses could be specified by the root-mean-square (RMS) widths obtained through the evaluation of second-order moments. The evaluation of the RMS temporal width can be done directly using the data from standard autocorrelation measurements; there exists a simple relationship between the RMS width of a pulse and the RMS width of its autocorrelation trace, irrespective of the pulse shape. Hence the approach is free from any assumption on the functional form of the pulse temporal profile; furthermore it does not require the full characterization of the amplitude and phase of the pulse.Based on the analogy with laser beams, we will introduce the definition of a Pulse Quality Factor proportional to the product of the spectral and temporal RMS widths. Such a definition eliminates subjective interpretations of autocorrelation traces and allows the definition of a generalized dispersion length. We will show that the Pulse Quality Factor is more representative of the pulse quality than the more conventional timebandwidth product. The measurement of the Pulse Quality Factor is easily accessible through already widespread measurement techniques.