A5002370746- Spectroscopy and Quantum Chemical Studies
- 2D Materials and Applications
- Photosynthetic Processes and Mechanisms
- Perovskite Materials and Applications
- Chalcogenide Semiconductor Thin Films
- Photoreceptor and optogenetics research
- Spectroscopy and Laser Applications
- Quantum Dots Synthesis And Properties
- Molecular Junctions and Nanostructures
- Advanced Fiber Laser Technologies
- Microbial Community Ecology and Physiology
- Granular flow and fluidized beds
- Orbital Angular Momentum in Optics
- Digital Holography and Microscopy
- Earthquake Detection and Analysis
- Landslides and related hazards
- Particle Dynamics in Fluid Flows
- Laser-Matter Interactions and Applications
- Geotechnical and Geomechanical Engineering
- Magnetic and Electromagnetic Effects
- Planetary Science and Exploration
- Advanced Chemical Physics Studies
- Hydraulic Fracturing and Reservoir Analysis
- Electrochemical Analysis and Applications
- Molecular spectroscopy and chirality
United States Naval Research Laboratory
2023-2024
Politecnico di Milano
2020-2023
University of Michigan
2015-2022
SLAC National Accelerator Laboratory
2012
Loyola University Chicago
2012
Office of Science
2012
Stanford Synchrotron Radiation Lightsource
2012
Significance The remarkable near-unity quantum efficiency of photosynthetic charge separation has motivated decades research to uncover the underlying design principles. Much our current understanding is rooted in studies bacterial reaction center (BRC). We present two-dimensional electronic spectroscopy BRC as it undergoes separation, resolving energy-transfer and charge-separation processes with time excitation frequency resolution. These measurements reveal excitonic structure BRC,...
Multidimensional spectroscopy is the optical analog to nuclear magnetic resonance, probing dynamical processes with ultrafast time resolution. At frequencies, technical challenges of multidimensional have hindered its progress until recently, where advances in laser sources and pulse-shaping removed many obstacles implementation. visible infrared (IR) regimes has already enabled respective our understanding photosynthesis structural rearrangements liquid water. A frontier extend combine...
Monolayer transition metal dichalcogenides (ML-TMDs) are two-dimensional semiconductors that stack to form heterostructures (HSs) with tailored electronic and optical properties. TMD/TMD-HSs like WS2/MoS2 have type II band alignment long-lived (nanosecond) interlayer excitons following sub-100 fs charge transfer (ICT) from the photoexcited intralayer exciton. While many studies demonstrated ultrafast nature of ICT processes, we still lack a clear physical understanding due trade-off between...
We report two-dimensional electronic spectroscopy (2DES) experiments on the bacterial reaction center (BRC) from purple bacteria, revealing hidden excitonic and vibronic structure. Through analysis of coherent dynamics BRC we resolve specific signatures that allow us to definitively assign upper exciton energy "special pair." This assignment is supported by simulations a reduced model BRC. The also identify nonsecular coherence transfer processes neglected in standard models photosynthetic...
Bacteriochlorophyll a (BChla) is the most abundant pigment found in Bacterial Reaction Center (BRC) and light-harvesting proteins of photosynthetic purple green bacteria. Recent two-dimensional electronic spectroscopy (2DES) studies pigment–protein complexes including BRC Fenna–Matthews–Olson (FMO) complex have shown oscillatory signals, or coherences, whose physical origin has been hotly debated. To better understand observations coherence larger systems, it important to carefully...
The bacterial reaction center (BRC) serves as an important model system for understanding the charge separation processes in photosynthesis. Knowledge of electronic structure BRC is critical its mechanism. While it well-accepted that "special pair" pigments are strongly coupled, degree coupling among other has been thought to be relatively weak. Here we study W(M250)V mutant by two-color two-dimensional spectroscopy correlate changes Q x region with excitation y transitions. resulting y-Q...
Managing light-matter interactions on timescales faster than the loss of electronic coherence is key for achieving full quantum control final products in solid-solid transformations. In this work, we demonstrate coherent photoinduced insulator-to-metal transition prototypical Mott insulator V$_2$O$_3$. Selective excitation a specific interband with two phase-locked light pulses manipulates orbital occupation correlated bands way that depends evolution superposition states. A comparison...
We study a layer of grains atop plate which oscillates sinusoidally in the direction gravity, using three-dimensional, time-dependent numerical solutions continuum equations to Navier-Stokes order as well hard-sphere molecular dynamics simulations. For high accelerational amplitudes plate, exhibits steady-state "density inversion" high-density portion is supported by lower-density portion. At low amplitudes, oscillatory time dependence that strongly correlated motion plate. show simulations...
As demands for optical materials with higher sensitivities, lower cost, and reduced size intensify across the electromagnetic spectrum, novel solutions beyond monolithic must be considered. With this motivation, we combine infrared colloidal nanocrystals (NCs) of different composition diameter into binary superlattices, a type 'artificial solid' where NCs are analogous to 'atoms.' These superlattices provide ability tailor desired optoelectronic properties through choice constituent NCs,...
Abstract Vertical heterostructures (HS) of transition metal dichalcogenides (TMDs) host interlayer excitons (ILX), with electrons and holes residing in different layers. With respect to their intralayer counterparts, ILX feature much longer lifetimes diffusion lengths, paving the way excitonic optoelectronic devices operating at room temperature. While recombination dynamics has been intensively studied, formation process its underlying physical mechanisms are still largely unexplored. Here...
We present two-dimensional electronic spectroscopic data from reaction centers of photosynthetic bacteria with excitation and detection bandwidths spanning the B, P, H absorption bands. fit population kinetics using global analysis.
The search for synthetic materials that mimic natural photosynthesis by converting solar energy into other more useful forms of is an ever-growing research endeavor. Graphene-based materials, with their exceptional electronic and optical properties, are exemplary candidates high-efficiency harvesting devices. High photoactivity can be conveniently achieved functionalizing graphene small molecule organic semiconductors whose band-gaps tuned structural modification, leading to interactions...
We present a comparative two-dimensional electronic spectroscopy study of coherent dynamics in the photosystem II reaction center, bacterial center and their constituent monomers pigments. discuss physical origin observed coherences.
Get PDF Email Share with Facebook Tweet This Post on reddit LinkedIn Add to CiteULike Mendeley BibSonomy Citation Copy Text A. Niedringhaus, V. R. Policht, and J. P. Ogilvie, "Probing Ultrafast Dynamics of Bacteriochlorophyll-a Using Pulse Shaping Based 2D Electronic Spectrometer a Degenerate OPA," in Conference Lasers Electro-Optics, OSA Technical Digest (online) (Optica Publishing Group, 2016), paper JTu5A.80. Export BibTex Endnote (RIS) HTML Plain alert Save article
Vertical heterostructures (HS) of transition metal dichalcogenides (TMDs) host interlayer excitons (ILX), with electrons and holes residing in different layers. With respect to their intralayer counterparts, ILX feature much longer lifetimes diffusion lengths, paving the way excitonic optoelectronic devices operating at room temperature. While recombination dynamics has been intensively studied, formation process its underlying physical mechanisms are still largely unexplored. Here we use...
We introduce shaping and characterization methods for femtosecond space-time beams with broadband correlations between their topological charges (up to ℓ = 80) spectral frequencies (covering nearly 50% of the visible spectrum).