ANALYSIS OF A METHOD OF PHASE MEASUREMENT OF ULTRASHORT PULSES IN THE FREQUENCY-DOMAIN

We perform a detailed analysis of our method of phase measurement of ultrashort light pulses; we show that the output pulse of a zero dispersion compressor with a mask consisting of a narrow slit is a wide pulse delayed an amount equal to the phase derivative of the field spectrum with respect to frequency. We also state criteria to know whether the approximations are valid. The method is not affected by artifacts coming from diffraction effects in the slit or by the fact that only correlations are measured. The effects of the errors in positioning the elements are considered and minimized in the construction of the experimental apparatus. We describe a novel technique for measurement of the derivative of the cross correlation, and we employ it to locate the delayed output pulse.