Propagation of laser pulses through any dispersive medium can cause deformation of the temporal shape of ultrashort pulses, which is detectable through their spectral phase derivatives called group-delay (GD), group-delay dispersion (GDD), third and higher order dispersions (TOD, FOD, etc.).
Spatiotemporal evolution of the pulses is more complicated if the surfaces of the media are not parallel, e.g. prisms and wedges diverts the propagation direction of different spectral components and hence spectrally disperses the beam. This effect is quantified by the angular dispersion, which has two different interpretations, depending on the approach: one defines by propagation directions, the other is by phase fronts. Difference occurs only when plane wave approximation cannot be applied.
The method called Spectrally and Spatially Resolved Interferometry (SSRI) – which is based on a combination of a two-beam interferometer and an two-dimensional imaging spectrograph – allows us the measure the spectral phase shift of any dispersive material with extremely high accuracy. With the use of an inverted interferometer, SSRI is capable to characterize the phase front angular dispersion. Meanwhile, the propagation direction angular dispersion can be measured simply by the two-dimensional spectrograph and a single achromatic lens.
Based on these techniques, CE Optics offers a complete system for phase- and angular dispersion characterization of ultrashort pulses. Both type of angular dispersions of ultrashort laser pulses can be determined with an extreme accuracy better than 0.1 /nm and the dispersion of bulk materials and chirped mirrors also under 1% relative error. Due to the simple realization it is easy to handle, does not require advanced skills, the alignment and measurement only take a few moments. Our devices are capable of real-time diagnostics also and independent of most pulse parameters including duration, energy, wavelength and polarization.