= Gerhard G. Paulus
{c}
\b[Gerhard G. Paulus] is a physicist whose Jena university profile identifies research in strong-field <laser> physics, attosecond physics and the absolute phase of very short optical pulses. The profile records a professorship in experimental physics and <nonlinear optics> beginning in 2007.<Gerhard G. Paulus professor profile by Friedrich Schiller University Jena>[Professorship and stated research fields]{ref}
A motivating experimental question is whether two pulses with the same intensity envelope can drive different electron motion. A simple original field model is
$$
E(t)=E_0e^{-t^2/(2\tau^2)}\cos(\omega_0t+\phi).
$$
Its <carrier-envelope phase> is $\phi$. At the envelope maximum $t=0$, choosing $\phi=0$ gives $E=E_0$, whereas $\phi=\pi/2$ gives $E=0$. The envelope is unchanged. This distinction is especially consequential for few-cycle pulses and processes that respond to the instantaneous <electric field>; it does not claim that all detectors resolve the carrier oscillation.
A 2017 account by the collaborating FAU experimental group describes a direct probe of focal phase: <photoelectric effect> at a nanometer-sharp tip was sensitive to <carrier-envelope phase>, and the tip was raster-scanned through the laser focus. The account explicitly identifies collaboration with Paulus's Jena group.<Optical phase in the focus of a pulsed laser beam measured in 3-d by the FAU Chair for Laser Physics>[Experimental probe, raster scan and collaborator attribution]{ref}
The important observable is a phase-sensitive electron response, rather than only a <light intensity> image. A focus can change the relative optical phases through the <Gouy phase>; for a pulse, the variation of focusing with <frequency> can also matter. The experiment connects a local material probe to the spatial waveform of a light pulse without assigning every coauthor's experimental step to Paulus individually.
\Image[https://www.physik.uni-jena.de/pafmedia/23340/paulus-gerhard-g-1968.avif?height=403&width=300]
{title=Gerhard G. Paulus; university professor-gallery portrait credited to Jan-Peter Kasper, Friedrich Schiller University Jena}
{height=403}
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