Allison Research Group

With the Levine group, we have posted a new paper about simulating transient absorption spectroscopy from first principles.

We have posted a new paper regarding imaging pseudospin dynamics in graphene. Working at the low excitation fluences enabled by our unique tr-ARPES instrument, we are able to vary the relative importance of electron-electron and electron-phonon scattering on the dynamics and also momentum-resolve the nascent photoexcited electrons before they relax. These are very challenging measurements due the very short carrier lifetimes in graphene and the need to resolve fine momentum-space features of the distributions.

Allison lab postdoc Alice Kunin will start as an assistant professor at Princeton in Jan. 2024 where she will continue to develop advanced photoelectron spectroscopy techniques. Princeton has made a news post with more details.

Our work resolving valley polarization dynamics in monolayer WS₂ is now featured as a DOE office of Science Highlight.

Sergii Chernov is leaving us soon to start a new position at PETRA III. It was great to get the whole group together, with both new students and seasoned veterans, for an evening out.

In collaboration with the Liu group and the Laser Teaching Center at Stony Brook University, we will begin an exciting new five-year project to develop high-power frequency combs covering a wide swath of the electromagnetic spectrum, from the THz to the soft x-ray. The project is funded by the the Major Research Instrumentation (MRI) program of the National Science Foundation. The official announcement from NSF can be found here.

We have now posted a paper regarding our results from time-resolved ARPES studies in monolayer tungsten disulfide:

https://arxiv.org/abs/2203.02419

The momentum-space images recorded via time-of-flight momentum microscopy, like the one shown at left,  enable detailed examination of the momentum and energy dependence of coupling between exciton states across the Brillouin zone.