Ultrashort Laser Pulse Phenomena, 2nd Edition

484 Diagnostic Techniques

9.4.5. Spectral Phase Interferometry for Direct

Electric Field Reconstruction (SPIDER)

Unlike the techniques discussed before SPIDER allows one to determine the

pulse shape and phase noniteratively by a set of linear transformations of the

measured data. The technique developed by Iaconis and Walmsley [47] is an

example of spectral shearing interferometry. Suppose we have two pulses that

are identical except that they are shifted in frequency with respect to each other

by an amount ω

s

(spectral shear). These two pulses are delayed in time by τ and

send into a spectrometer. At the output of the spectrometer, using a quadratic

integrating detector, we measure a signal proportional to the square of the sum

of the spectral fields ...