Bulletin of the American Physical Society
APS March Meeting 2023
Volume 68, Number 3
Las Vegas, Nevada (March 5-10)
Virtual (March 20-22); Time Zone: Pacific Time
Session Y51: Ultrafast dynamics in condensed-phase systems.Invited
|
Hide Abstracts |
Sponsoring Units: DAMOP Chair: Michael te Vrugt, University of Muenster Room: Room 321 |
Friday, March 10, 2023 8:00AM - 8:36AM |
Y51.00001: Integrated optical-field sampling with petahertz electronics Invited Speaker: Mina R Bionta Sub-cycle resolution sampling of arbitrary electric fields in time allows complete analysis of a system's electromagnetic response. This allows for many applications from tracking physical phenomena to biology and medicine. However, challenges arise when scaling to sampling visible and near-IR waveforms as these regimes ostensibly require high-energy optical sources and/or complicated apparatus. We circumvent these difficulties by using a chip-based approach that uses strong-field driven photoemission from plasmonic nanoantennas to generate attosecond electron bursts enabling a bandwidth greater than 1 PHz. Our integrated devices can sample arbitrary, low-energy waveforms, under ambient conditions, with attosecond time-resolution all on a chip. By tailoring the symmetry and arrangement of the patterned nanoantennas we can tune the responsivity of the devices for selective measurements. We have reconstructed the complete incident field illuminating our devices in amplitude, and phase, and demonstrated polarization sensitivity and selective sampling of specific polarizations. Additionally, we have shown how our time-resolved measurements of physical phenomena such as solid-state high harmonic generation can be used to tease apart the interplay of intra- and interband dynamics generating these high-order photons. Our work demonstrates a compact all-on-chip sampling technology with the requisite bandwidth and field sensitivity for myriad applications, enabling time-domain, optical-field-resolved spectroscopy of low-energy optical waveforms spanning visible to mid-infrared and even THz wavelengths. |
Friday, March 10, 2023 8:36AM - 9:12AM |
Y51.00002: High-harmonic generation in solids: imperfect recollisions, multiband effects and anomalous currents Invited Speaker: Lun Yue High-harmonic generation (HHG) has emerged in recent years as an all-optical probe of ultrafast dynamics and static properties of materials. Here, I report on our recent theoretical findings on the microscopic mechanisms behind HHG, as well as potential spectroscopy applications of HHG. |
Friday, March 10, 2023 9:12AM - 9:48AM |
Y51.00003: Imaging the graphene electron motion in real time and space Invited Speaker: Mohammed T Hassan Ultrafast Electron Diffraction and Microscopy imaging have been demonstrated to be pivot tools for imaging the atomic motion in real-time and space[1-3]. The generation of a few hundred femtoseconds electron pulses enabled recording movies for molecular and atomic motion. However, the technical challenges in electron pulse compression have limited the temporal resolution of electron imaging experiments to a hundred femtoseconds. Here, we demonstrate the attosecond temporal resolution by generating attosecond electron pulses in the transmission electron microscope to establish what we so-called “Attomicroscopy”. Moreover, we utilized the Attomicroscopy to image the electron motion dynamics in graphene. In a strong field, the electron is moving in the reciprocal space around the Dirac point following the waveform of the driver field. The attosecond electron diffraction experiment allowed us to extract the electron density distribution in the reciprocal space at different time instants and connect it with the electron motion in real space. The demonstrated Attomicroscopy imaging tool opens the avenue to study electron motion in neutral matter and promises new electron imaging applications in physics, chemistry, and biochemistry.
|
Friday, March 10, 2023 9:48AM - 10:24AM |
Y51.00004: The mechanism of high harmonic generation in liquids and its application to electron scattering spectroscopy Invited Speaker: Ofer Neufeld High harmonic generation (HHG) takes place in all phases of matter. In gases it has been extensively studied and is well-understood. In solids research is ongoing, but a consensus is forming for the dominant HHG mechanisms. In liquids however, no established theoretical model exits yet, and approaches developed for gases and solids are generally inapplicable. Here there are many open questions such as cutoff scaling laws, the dominant HHG mechanisms, and more. Advancement on this front may lead to novel light sources, and are especially appealing for ultrafast spectroscopy of chemistry in solutions. In particular, the great success of high harmonic spectroscopy in both gas and solid phases motivates extending this technique to the liquid phase, but this is hindered by the lack of a microscopic understanding of the underlying light-driven electron dynamics. In this talk, I will present our recent collaborative effort in tackling this problem by combining HHG experiments from thin liquid flat jets, and theory based on a novel ab-initio approach that relies on clusters we have developed. We have employed these techniques to study HHG in different liquids and laser conditions, focusing on the microscopic mechanism and the cutoff scaling. Surprisingly, and opposed to the established cutoff scaling in gases and solids, we found that the liquid HHG cutoff does not scale with the driving wavelength, and scales very weakly with the driving power. We propose an extended semi-classical model which takes into account the electron-ion scattering processes in the liquid to explain our findings. The simple model qualitatively describes the main structure of the HHG spectra, and identifies the electron mean free paths as a principal factor in the HHG process in liquids. Our work thus paves the way to the utilization of HHG spectroscopy for probing electron mean free paths in liquids in the low energy regime (<10eV), and has potential for probing ultrafast chemistry in solutions. |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700