1. Autocorrelator:

2. Intensity Autocorrelator:
SHG
crystal
Variable delay, t
Detector
Beam
splitter
E(t)
E(t–t)
Esig(t,t)
The signal field is E(t) E(t-t).
So the signal intensity is I(t) I(t-t)
Pulse to be measured

3. Autocorrelation

4. Regular + Intensity A.C:
Spectrum: Amp. + Phase
Pulse 1:
Intensity Autocorrelation (both pulses)
Pulse 2:

5. SPIDER

6. SPIDER

7. FROG SHG FROG is simply a spectrally resolved autocorrelation.
crystal
Pulse to be measured
Variable delay, t
Camera
Spec-
trometer
Beam
splitter
E(t)
E(t–t)
Esig(t,t)= E(t)E(t-t)
SHG FROG is the most sensitive version of FROG.
SHG FROG is simply a spectrally resolved autocorrelation.