Bulletin of the American Physical Society
52nd Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics
Volume 66, Number 6
Monday–Friday, May 31–June 4 2021; Virtual; Time Zone: Central Daylight Time, USA
Session C03: Ultrafast and strong-field dynamics in the condensed phaseLive
|
Hide Abstracts |
Chair: Robert Baker, Ohio State University |
Tuesday, June 1, 2021 10:30AM - 10:42AM Live |
C03.00001: Tabletop Attosecond Four-Wave Mixing Spectroscopy of Core-Exciton Dynamics in Solids: Studies of NaCl James D Gaynor, Ashley Fidler, Yen-Cheng Lin, Hung-Tzu Chang, Michael Zuerch, Daniel M Neumark, Stephen R Leone Nonlinear wave-mixing in solids with ultrafast extreme ultraviolet (XUV) and X-rays can provide new insight into complex electronic dynamics of materials. This study demonstrates that tabletop-based attosecond four-wave mixing (FWM) spectroscopy is a viable approach to studying atom-like, highly localized core-excitonic dynamics in solid-state materials. Attosecond FWM uses one XUV pulse obtained by high harmonic generation and two separately timed few-cycle near-infrared (NIR) pulses arranged non-collinearly to generate a spatially distinct background-free emission. The dynamics of the Na+ L2,3 edge core-excitons in NaCl around 33.5 eV are characterized here. An inhomogeneous distribution of core-excitons underlying the well-known doublet absorption of the Na+ -point core-exciton spectrum is deconvoluted by the resonance-enhanced nonlinear FWM signals. Dark core-excitonic states that are coupled to the XUV-allowed levels through the NIR pulses are also characterized spectrally and temporally. Approximate sub-10 femtosecond coherence lifetimes of the core-exciton states are reported. The observed dynamics are discussed in the context of electron-hole exchange interactions, electron-electron correlation, and electron-phonon broadening. This investigation successfully indicates that tabletop attosecond FWM spectroscopies represent a viable technique for time-resolved solid-state measurements. |
Tuesday, June 1, 2021 10:42AM - 10:54AM Live |
C03.00002: Edge state contributions to high-order harmonic generation in topological condensed matter Christoph Juerss, Dieter Bauer In topological insulators the edge states connect the well separated valence and conduction band in momentum space and allow an electronic current flow along the edges of a finite system. As shown in studies before, these edge states can have a significant impact on the generation of harmonic spectra. In this work we simulated the harmonic spectra of two graphene-like flakes with different edge configurations. The harmonic spectra are compared to the spectrum of the bulk where edge states are absent. However, for the non-trivial topological phase of the finite flakes edge states occur. The edge states in momentum space can be manipulated by the edge configuration of the flakes. We investigate how the different electron dynamics with and without edges are reflected in the harmonic spectra for finite flakes and bulk, respectively. |
Tuesday, June 1, 2021 10:54AM - 11:06AM Live |
C03.00003: Significance of the full Brillouin zone in electron-hole recollisions in solid-state high-harmonic generation Lun Yue, Mette B Gaarde High-harmonic generation (HHG) in solids has exciting prospects for the engineeing of compact ultrafast light sources and the ultrafast probing of band structures and topology. The recollision model for HHG consisting of tunneling, propagation and recollision, has been instrumental to our understanding of HHG in the gas- and condensed-matter phases. We theoretically show that in solids, the recollision picture should be expanded to be able to describe situations of current theoretical and experimental interest. Specifically, for a bulk solid irradiated by elliptically polarized pulses and a monolayer material irradiated by linearly polarized pulses, we show that A) electron-hole pairs created away from the minimal band gap can dominate and B) the imperfect recollisions (where the electron and hole are spatially separated) can play important roles. Our methodology consists of the numerical solutions to the SBEs, an extended recollision model, and a wave-packet approach. |
Tuesday, June 1, 2021 11:06AM - 11:18AM Live |
C03.00004: High-harmonic generation in metalic titanium nitride Aleksey Korobenko, Soham S Saha, Alan T Godfrey, Marina Gertsvolf, Andrei Naumov, David M Villeneuve, Alexandra Boltasseva, Vladimir M Shalaev, Paul B Corkum High-harmonic generation is the cornerstone of nonlinear optics. Having been demonstrated in a wide range of crystalline systems, including dielectrics, semiconductors, and semi-metals, as well as in gases, it left metals out due to their low damage threshold. We report on the high-harmonic generation in metallic titanium nitride (TiN) films, a refractory plasmonic metal, known for its high melting temperature and laser damage threshold. We show that TiN can withstand few-cycle infrared laser pulses with peak intensities as high as 13 TW/cm2, enabling the emission of intraband harmonics up to photon energies of 11 eV. We study the intensity and angle dependence of the harmonic yield and compare them with the numerical calculations. We show that the intensity scaling and angular anisotropy of the emitted VUV radiation is consistent with the the anisotropic conduction band structure of TiN. The metal harmonics will allow establish the link between the fields of solid and plasma HHG. They also pave the way for compact and efficient plasmonic devices producing vacuum ultraviolet (VUV) frequency combs. |
Tuesday, June 1, 2021 11:18AM - 11:30AM Live |
C03.00005: High harmonics from backscattering of delocalized electrons Chuan Yu, Ulf Saalmann, Jan M Rost
|
Tuesday, June 1, 2021 11:30AM - 11:42AM Live |
C03.00006: Fingerprints of Majorana fermions in high-harmonic spectroscopy Gopal Dixit, Adip Pattanayak, Sumiran Pujari Majorana fermions [1], due to the equivalent character of their particle and antiparticle, have found applications in various scientific areas like solid state physics, nuclear and particle physics. Till date, the presence of Majorana fermions in solid state systems is under vigorous debate. HHG in solids became a method of choice to probe different aspects of solids such as examining the dynamics of the defects in solids [2,3] and probe localisation-delocalisation phase transition [4] in condensed matter systems. In this work, we provide an alternative method to see the signatures of the Majorana fermions without ambiguity using ultrashort laser pulses and high-harmonic spectroscopy. We show that the nonlinear optical response of a system is able to sense the presence of Majorana fermions. The one-dimensional superconducting chain originally proposed by A. Kitaev that hosts Majorana edge modes in its topological phase is considered as the model system. We show non-resonant light fields probe topological–trivial superconducting phase transition in a system with edges, i.e., open boundary conditions. The sensitivity of high-harmonic spectroscopy to the superconducting phase transition to trace the signature of Majorana edge modes as their population dynamics are different than other modes in the bulk. Moreover, the high-harmonic spectroscopy becomes insensitive to the phase transition with similar harmonic profiles in both phases for systems with periodic boundary conditions when Majorana-zero-modes (MZMs) are absent. Moreover, we show that the harmonic spectra obtained from Bogoliubov-de Gennes (BdG) form of the Hamiltonian and from the many-body Kitaev superconducting Hamiltonian are same. |
Tuesday, June 1, 2021 11:42AM - 11:54AM Live |
C03.00007: Elliptically Polarized High-order Harmonic Generation from Solids Driven by Linearly Polarized Mid-Infrared Pulse Combined with Terahertz Field Yaguo Tang, Sha Li, Bradford K Talbert, Cosmin Blaga, Pierre Agostini, Louis F DiMauro Perturbing and/or controlling high-order harmonic generation (HHG) from gases by (quasi-)static electric fields have been proposed since long ago, but never been realized in experiments, due to the difficulty of introducing strong enough (quasi-)static fields. For example, in Phys. Rev. Lett. 85, 732 (2000), theoretical investigation predicts that in the presence of a static field, elliptically polarized high-order harmonics can be generated by linearly polarized driving laser field. HHG from solids offers an alternative platform to test those theories due to the lower prerequisite on driving laser intensity. In this study, we experimentally demonstrate for the first time the generation of elliptically polarized even-order high harmonics from solid (100 nm, polycrystalline ZnO thin film) driven by a linearly polarized mid-infrared (70 fs, 3.6 μm) pulse dressed by a weak linearly polarized single-cycle terahertz (2 ps, 600 μm) pulse. We show that both the ellipticity and the orientation of the polarization ellipse depend on the angle (θ) between the mid-infrared and THz polarizations and vary across harmonic orders. For example, at θ=80°, the ellipticity varies from 0 to 0.4 and the major axis of the polarization ellipse varies by ~25 degrees, across 6th to 18th harmonic orders. Our study provides a novel way of generating elliptically polarized high harmonic lights. Exploring the origin of harmonic ellipticity would help us better understand the HHG process in solids. |
Tuesday, June 1, 2021 11:54AM - 12:06PM Live |
C03.00008: Wavelength scaling of electron collision times in filament-produced plasma in solids GARIMA C NAGAR, Dennis Dempsey, Bonggu Shim We report an anomalous regime of laser-matter interactions, which is created by the wavelength dependence of electron collision time during filamentation in solids. Experiments are performed using femtosecond-time-resolved interferometry by varying the filament driver wavelength from 1.2 to 2.3 μm and using a 0.8-μm probe. Information on the phase and absorption via interferometry enables simultaneous measurements of plasma densities and electron collision times during filamentation. Although it is expected that the plasma density decreases with increasing wavelength due to larger plasma-defocusing at longer wavelengths [1-4], our measured plasma densities are nearly constant for all the pump wavelengths. This observation is successfully explained by the measured wavelength-dependence of electron collision time: electron collision times in filament-produced plasma decrease with increasing wavelength, which creates an anomalous regime of plasma-defocusing where longer wavelengths experience smaller plasma defocusing. In addition, simulations with the measured electron collision times successfully reproduce the observed plasma density scaling with wavelength [5]. [1] L. Bergé et al., Phys. Rev. A 88, 023816 (2013). [2] Y. E. Geints et al., Appl. Opt. 56, 1397 (2017). [3] S. Tochitsky et al., Nat. Photonics 13, 41 (2019). [4] R. I. Grynko et al., Phys. Rev. A 98, 023844 (2018). [5] Nagar et al., submitted. |
Tuesday, June 1, 2021 12:06PM - 12:18PM Live |
C03.00009: Sampling Laser Waveforms using Tunneling in Solids Shima Gholam-Mirzae, Yangyang Liu, John E Beetar, Jonathan Nesper, Ahmed Yousif, Nrisimha Murty Madugula, Michael Chini Characterizing the time-dependent electric field waveform of few-cycle laser pulses is a requirement for applications to attosecond science and other field-resolved spectroscopies. Recently, characterization techniques based on strong-field excitation have shown success in characterizing few-cycle pulses and waveforms ranging from the ultraviolet to mid-infrared. Unlike perturbative nonlinear optical techniques, these characterization methods do not rely on phase matching or retrieval algorithms, and they have been demonstrated to accurately characterize broad bandwidth pulses and sub-optical cycle field transients. Here, we extend one such technique, known as TIPTOE (tunneling ionization with a perturbation for time-domain observation of an electric field), to solid-state media. We show that tunneling and multiphoton excitation in a dielectric solid can provide an ultrafast temporal gate, as well as a simple detection scheme, for waveform characterization. The solid-state TIPTOE allows for full measurement of the electric field waveform from sources with relatively low pulse energies in comparison to the gas-phase TIPTOE. Furthermore, we experimentally demonstrate that the solid-state platform allows for single-shot, on-chip measurement of optical waveforms. |
Tuesday, June 1, 2021 12:18PM - 12:30PM Live |
C03.00010: Investigating Plasmonic Resonances in Metal/Semiconductor Heterostructures Joseph P Avenoso, Meng Jia, Oludare Babawale, Lars Gundlach Metal/semiconductor heterostructures have shown promise in the field of plasmonics, with possible applications towards solar energy conversion, opto-electronics, and photocatalysis. In particular, plasmon-induced transfer of carriers from the metal to semiconductor components of the system is not yet well understood, let alone the material properties that would most enhance this plasmon-induced transfer. Therefore, ultrafast spectroscopic measurements on various heterostructures with tuned properties are required. The chosen systems of study are two-dimensional Au/Cu2O hemispherical nano-heterostructure arrays. By varying the semi-shell thickness, we can tune the plasmonic resonance, and ultimately the plasmonic coupling and the corresponding charge transfer processes. Charge transfer mechanisms of these systems are studied with transient absorption spectroscopy (TAS) and time-domain terahertz spectroscopy (TDTS). Hot hole dynamics are extracted from the TAS measurements, while TDTS further investigates the plasmonic properties. Results show that wavelength-dependent hot hole transfer that occurs after the localized surface plasmon undergoes Landau damping, and that terahertz emission from these nano-heterostructure arrays are dependent on the metal atom used for the core as well as the core-shell size. This study could be expanded to a broader range of metal-semiconductor hybrids, where the fine-tuning of their properties can lead to the design of optimized plasmonic materials. |
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