Ultrashort Pulse - Measurement Techniques

Measurement Techniques

Several techniques are available to measure ultrashort optical pulses:

• intensity autocorrelation: gives the pulse width when a particular pulse shape is assumed.

• spectral interferometry (SI): a linear technique that can be used when a pre-characterized reference pulse is available. Gives the intensity and phase. The algorithm that extracts the intensity and phase from the SI signal is direct.

• Spectral phase interferometry for direct electric-field reconstruction (SPIDER): a nonlinear self-referencing technique based on spectral shearing interferometry. The method is similar to SI, except that the reference pulse is a spectrally shifted replica of itself, allowing one to obtain the spectral intensity and phase of the probe pulse via a direct FFT filtering routine similar to SI, but which requires integration of the phase extracted from the interferogram to obtain the probe pulse phase.

• Frequency-resolved optical gating (FROG): a nonlinear technique that yields the intensity and phase of a pulse. It's just a spectrally resolved autocorrelation. The algorithm that extracts the intensity and phase from a FROG trace is iterative.
• Grating-eliminated no-nonsense observation of ultrafast incident laser light e-fields (GRENOUILLE), a simplified version of FROG. (Grenouille is French for "frog".)

Methods of characterizing and controlling the ultrashort optical pulses:

• MIIPS Multiphoton Intrapulse Interference Phase Scan, a method to characterize and manipulate the ultrashort pulse.