this week’s #AttoFridays will take place on the 10th of March, at 3pm London time. Our speaker will be Professor James Cryan (PULSE Institute, Stanford). He will talk about Probing #Attosecond #Electron Dynamics with X-ray #Free #Electron #Lasers. Below you will find a brief bio and abstract.

Title: Probing Attosecond Electron Dynamics with X-ray Free Electron Lasers

Abstract:

Electron motion is a key ingredient of chemical reactions. For small quantum systems, the natural timescale for such electronic motion is typically in the range of tens to hundreds of attoseconds. Consequently, the study of ultrafast electronic phenomena requires the generation of laser pulses shorter than 1 fs, and of sufficient intensity to drive multiple interactions with the target. Free Electron Lasers (FELs), such as the Linac Coherent Light Source (LCLS), are now able to achieve these conditions, allowing for the probing of electron dynamics on this natural time scale, elucidating the earliest processes involved in chemical change.

In my talk, I will present our first results demonstrating nonlinear spectroscopies such as pump/probe spectroscopy, and X-ray wave mixing making use of this unique source. We demonstrated the preparation of a coherent electronic wavepacket by driving stimulated X-ray Raman scattering. Combing attosecond X-ray pulses with an external laser field we are able to time-resolve the photoemission dynamics of core-level electrons in molecules. I will also present a first result in attosecond-pump/attosecond-probe spectroscopy.  

Bio:

James Cryan is a Staff Scientist at SLAC National Accelerator Laboratory. He is the head of the AMO Sciences Department at LCLS, and he is a member of the Stanford PULSE Institute, where leads the attosecond science group. James’ research focuses on studying electron dynamics on the attosecond time scale and developing tools to better probe these phenomena. James is also the lead instrument scientist for the time-resolved molecular and optical sciences (TMO) hutch at the LCLS, a soft x-ray spectroscopy hutch which specializes in gas phase samples.  

James completed his undergraduate education at The Ohio State University. He received his PhD in physics from Stanford University in 2012. From 2012 to 2014, James was a Postdoctoral scholar in the Chemical Sciences Division at Lawrence Berkeley National Laboratory. In 2015 he joined SLAC as a Staff Scientist in the Stanford PULSE Institute.  In 2012, James won the Spicer Young Investigator award for his thesis work at the LCLS. In 2020, James was elected a fellow to the American Physical Society. 

Registration is free at

Welcome! You are invited to join a webinar: Atto Fridays – James Cryan – Probing Attosecond Electron Dynamics with X-ray Free Electron Lasers. After registering, you will receive a confirmation email about joining the webinar. Prof. James P. Cryan (Stanford PULSE Institute) Probing Attosecond Electron Dynamics with X-ray Free Electron Lasers — Following up on the success of our virtual Workshop “Quantum Battles in Attoscience” in July 2020, with more than 300 participants from 35 countries, we are organizing a virtual seminar series on Fridays at 3pm London time, the “Atto Fridays”. us02web.zoom.us

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Alternatively, you can watch the talk live on YouTube as a passive viewer

Quantum Battles www.youtube.com

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All welcome!

The Atto Fridays team (Carla Faria, Lidice Cruz Rodriguez, Sufia Hashim and Thomas Rook)

Dr. Manish Garg
Max Planck Institute for Solid State Research, Germany
Tuesday, 21 March 2023 12:00
Place: Conference room (IMDEA Nanociencia). 

Abstract: 

Motion of electrons is at the heart of any chemical transformation, photo-induced charge or energy transfer process in molecules. Contemporary techniques in ultrafast science have the capability to generate and trace the consequences of this motion in real-time, but not in real-space. Scanning tunnelling microscopy (STM), on the other hand, can locally probe the valence electron density in molecules, but cannot provide by itself dynamical information at this ultrafast time scale. In my talk, I will show you how dynamics of coherent superposition
of valence electron states generated by < 5 femtosecond long carrier-envelope-phase (CEP) stable laser pulses, can be locally probed with angstrom-scale spatial resolution and 300 attosecond temporal resolution simultaneously, at the single orbital-level with the help of an STM, defying the previously established fundamental space-time limits [1-4].
Electronic motion in molecules is usually coupled with atomic motion, especially in molecules undergoing photo-induced charge/energy transfer, structural or chemical transformation. In order to understand this coupling, we have recently realized femtosecond broadband coherent anti-Stokes Raman spectroscopy (CARS) in an STM and it has enabled tracking of coherent atomic motions in a single graphene nanoribbon with subangstrom scale spatial, meV energy and ~30 fs temporal resolution, simultaneously [5-6]. Time-resolved CARS implemented in an STM is the key to probing both electronic and atomic motion at the same time.

1. Garg et al. Nature 359-363, 538 (2016).
2. Gutzler, Garg et al. Nature Reviews Physics 3, 441-453 (2021).
3. Garg et al., Nature Photonics, 16, 196-202 (2022).
4. Garg and Kern. Science 367 (6476), 411-415 (2020).
5. Luo et al. Nano Letters 22 (13), 5100-5106 (2022).
6. Luo et al. Under Review (2022). arXiv:2210.02561