Prof. C. Trallero awarded multiple research grants
Professor Carlos Trallero has been granted $1.06 million from the Department of Defense, the U.S. Air Force and the Air Force Office of Scientific Research to study recollision physics at the nanoscale to help develop ultrafast electronics. This research will enhance the knowledge base of electron recollision dynamics at the nanoscale, which can be used to develop ultrafast light-driven electronics.
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Ultracold group achieves new milestone in quantum control
December 19, 2017 – Colin Poitras – UConn Communications Scientists from three major research universities successfully manipulated the outcome of a chemical reaction and, in doing so, created a rare molecular ion. Through a process known as “controlling chemistry,” the researchers bonded an oxygen atom to two different metal atoms, creating the barium-oxygen-calcium molecular ion or BaOCa+ The same […]
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Undergraduate Sam Entner traps cold atoms in Physics lab for summer research project
As a research assistant in the physics department at UCONN, I assisted in the alignment, maintenance, and principles of operation of the various apparatuses and measurement techniques used within cold atomic, molecular, and optical (AMO) experimental physics research. This included optical components, laser alignment, laser locking, saturation absorption spectroscopy, and electrodynamic ion trapping. Some specific […]
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Dr. Jan M Rost, Max Planck Institute for the Physics of Complex Systems, Dresden, Germany, Atomic, Molecular, and Optical Physics Seminar2:00pm
8/21
Dr. Jan M Rost, Max Planck Institute for the Physics of Complex Systems, Dresden, Germany, Atomic, Molecular, and Optical Physics Seminar
Wednesday, August 21st, 2019
02:00 PM - 03:00 PM
Storrs Campus GS-119
Dr. Jan M Rost,
Max Planck Institute for the Physics of Complex Systems,
Dresden, Germany
Sculpting electron dynamics through its environment
Interfacing an electron with a well-controlled environment can generate unusual dynamics, in particular if the electron is easily polarizable. The Rydberg Composite, a highly excited Rydberg electron whose spatial density encompasses many atoms or molecules on sites of a designed spatial lattice is one example. We will show that a 2D Composite with a two-dimensional lattice in form of an atomic monolayer has a particularly reach electron spectrum which features energy bands and exhibits regular as well as chaotic features depending on the ratio of lattice spacing and the wavelength of the Rydberg wave function. Possibilities for experimental realizations in the ultracold will be discussed.
The second part of the talk concerns noisy photo electron spectra as generated, e.g., by short and intense SASE free electron laser pulses. Learning the corresponding electron dynamics with a deep neural network by introducing synthetic Hamilton matrices, we can purify the spectrum as if it would have been created with a normal Gaussian pulse. Perspectives of this novel way to construct ultrafast electron dynamics from given noisy spectra will be discussed. -
Atomic, Molecular, and Optical Physics Seminar2:15pm
5/2
Atomic, Molecular, and Optical Physics Seminar
Thursday, May 2nd, 2019
02:15 PM - 03:15 PM
Storrs Campus Physics Building, P121
Dr. Ryan Carollo,
Department of Physics and Astronomy, Bates College
Blowing Bubbles... in Space!
Bose-Einstein condensates (BECs) can be used as sensitive probes or tests of delicate physics. However, gravitational sag equivalent to 100 nanokelvin per micron can adversely affect sensitive measurements or delicate potentials. NASA and JPL have solved this problem by installing a BEC machine (the Cold Atom Laboratory - CAL) on the International Space Station. We're using it to blow bubbles - fully-connected, quasi-2-dimensional shells of weakly-trapped condensate - and study them in a shape that can't be achieved on Earth. -
Dr. Adam Summers, Department of Physics, Kansas State University, "Ultrafast, Strong-Field Investigation of Nanosystems", Atomic, Molecular, and Optical Physics Seminar1:30pm
3/14
Dr. Adam Summers, Department of Physics, Kansas State University, "Ultrafast, Strong-Field Investigation of Nanosystems", Atomic, Molecular, and Optical Physics Seminar
Thursday, March 14th, 2019
01:30 PM - 02:30 PM
Storrs Campus Physics Building, P103A
Dr. Adam Summers, Department of Physics, Kansas State University
Ultrafast, Strong-Field Investigation of Nanosystems
Here I present work investigating the evolution of various nanosystems in extremely intense, ultrafast laser pulses. We study the dynamical processes initiated in these nanosystems over five order of magnitude of peak laser intensity, from 10^10 W/cm2 to 10^15 W/cm2. Specific processes include: thermal evolution and damage of nanowires under irradiation of a train of intense pulses, photoelectron reqscattering on the surface of nanoparticles, plasmonic enhancements of photoionization and the ultrafast formation of nanoplasmas from nanoparticles. -
Dr. Catherine Kealhofer, Department of Physics, Williams College, "Generating and controlling ultrafast electron pulses for time-resolved electron diffraction", Atomic, Molecular, and Optical Physics Seminar3:30pm
3/11
Dr. Catherine Kealhofer, Department of Physics, Williams College, "Generating and controlling ultrafast electron pulses for time-resolved electron diffraction", Atomic, Molecular, and Optical Physics Seminar
Monday, March 11th, 2019
03:30 PM - 04:30 PM
Storrs Campus Physics Building, P121
Dr. Catherine Kealhofer,
Department of Physics,
Williams College
Generating and controlling ultrafast electron pulses for time-resolved electron diffraction
Ultrafast electron diffraction (UED) is a powerful technique that lets us measure the positions of atoms in a crystal as they evolve during chemical and physical transformations. These measurements can give insight into how materials work on a microscopic level as well as guide the design of devices that respond on fast timescales. For some time, the best-available time resolution in UED has hovered around 100 fs (1 fs =10-15 s), just shy of the 10 fs resolution required to see the fastest atomic motions. In my talk, I'll explain how ultrafast electron diffraction works and why it's challenging to break the 100-fs resolution barrier. I'll show experimental results on a recent technique that uses terahertz electromagnetic fields to compress electron pulses in time. This technique has the potential to improve the resolution of UED below 100 fs and maybe even below ~1 fs, into the regime of electronic dynamics. The talk will also introduce ultrafast electron sources based on laser-triggered electron emission from nanometrically sharp metal tips. Not only is the physics of ultrafast electron emission in this system very rich, but the extraordinarily small source size in comparison with typical ultrafast flat photocathode sources can dramatically improve the beam quality, leading to smaller probe sizes, higher quality diffraction patterns, and enabling new techniques like ultrafast electron holography. -
Ben Augenbraun, Harvard University, "Laser-cooled polyatomic molecules for improved precision measurements", Atomic, Molecular, and Optical Physics Seminar2:00pm
2/5
Ben Augenbraun, Harvard University, "Laser-cooled polyatomic molecules for improved precision measurements", Atomic, Molecular, and Optical Physics Seminar
Tuesday, February 5th, 2019
02:00 PM - 03:00 PM
Storrs Campus Gant West Building, GW121
Ben Augenbraun,
Harvard University
Laser-cooled polyatomic molecules for improved precision measurements
Ultracold molecules are a promising platform for applications in myriad fields, ranging from quantum simulation and chemistry to precision tests of fundamental physics. Recent work on the direct laser cooling of molecules has brought a number of diatomic molecules to the ultracold regime. These molecules are representative of a large, diverse class of molecules amenable to laser cooling. In this talk, we will focus on how polyatomic molecules (with three or more atoms) offer qualitatively new and powerful features, and the interesting physics of laser cooling polyatomic molecules will be described. We will discuss experimental work in the Doyle group on laser cooling CaF and SrOH molecules, and introduce a new experiment aimed at laser cooling of polyatomic molecules with high sensitivity to Beyond-the-Standard-Model physics, including YbOH and YbOCH3. -
Dr. Marko Gacesa, BAER Institute / NASA Ames Research Center, "Photoassociation of ultracold molecular ions and controlling atom-ion charge exchange using magnetic Feshbach resonances", Atomic, Molecular, and Optical Physics Seminar4:00pm
12/10
Dr. Marko Gacesa, BAER Institute / NASA Ames Research Center, "Photoassociation of ultracold molecular ions and controlling atom-ion charge exchange using magnetic Feshbach resonances", Atomic, Molecular, and Optical Physics Seminar
Monday, December 10th, 2018
04:00 PM - 05:00 PM
Storrs Campus Physics Building, P121
Dr. Marko Gacesa,
BAER Institute / NASA Ames Research Center
Photoassociation of ultracold molecular ions and controlling atom-ion charge exchange using magnetic Feshbach resonances
Feshbach resonances offer a way to control the strength and sign of particle-particle interactions in ultracold atomic and molecular gases by tuning external magnetic or electric fields. This discovery led to a number of experimental applications in ultracold AMO physics, in particular in preparation and production of dense samples of ultracold molecules. Because of their importance, Feshbach resonances have been measured and characterized in numerous of neutral diatomic mixtures. A natural generalization of studies of neutral ultracold gases includes atom-ion mixtures, which remain much less investigated than neutral systems. Atom-ion interactions are, generally, more difficult to investigate due to their long-range nature and presence of the charge. Nevertheless, the same properties also offer a window to investigate different physical regimes than the ones accessible by the neutral systems.
In this talk, I will present recent results, obtained in collaboration with the group of Prof. Robin Cote, related to using external magnetic and electric fields in controlling charge-exchange in atom-ion collisions. Specifically, I will present our theoretical investigation of magnetic Feshbach resonances and their application to controlled charge transfer in \({}^{9,10}\)Be + \({}^{9,10}\)Be+, and \({}^{40}\)Ca+\({}^{43}\)Ca+ both of which are good model systems for heavier and more complex elements. I will also present the results of first theoretical study of photoassociative formation of cold molecular ions, where we estimated the production rates of NaCa+ molecular ions from trapped cold Na+ ions and Ca atoms. This study is based on experiments conducted in the group of Prof. W. Smith at UConn. -
Dr. Thomas Allison Stony Brook University, Atomic, Molecular, and Optical Physics Seminar4:00pm
12/3
Dr. Thomas Allison Stony Brook University, Atomic, Molecular, and Optical Physics Seminar
Monday, December 3rd, 2018
04:00 PM - 05:00 PM
Storrs Campus Physics Building, P121
Dr. Thomas Allison
Stony Brook University
Cavity-enhanced ultrafast spectroscopy: ultrafast meets ultrasensitive
Ultrafast optical spectroscopy methods, such as transient absorption spectroscopy and 2D spectroscopy, are widely used across many disciplines. However, these techniques are typically restricted to optically thick samples, such as solids and liquid solutions. Using a frequency comb laser and optical cavities, we present a technique for performing ultrafast optical spectroscopy with high sensitivity, enabling work in dilute gas-phase molecular beams. Resonantly enhancing the probe pulses, we demonstrate transient absorption measurements with a detection limit of \(\Delta OD = 2 \times 10^{−10}\) (\(1 \times 10^{-9} / \sqrt{Hz}\)). Resonantly enhancing the pump pulses allows us to produce a high excitation fraction at a high repetition rate, so that signals can be recorded from samples with optical densities as low as \(OD ≈ 10^{−8}\), or column densities \( < 10^{10}\) molecules∕cm\(^2\). In this talk, I will discuss initial demonstration experiments, methods for cavity-enhancing multidimensional spectroscopy signals using multiple frequency combs, and progress towards widely tunable cavity-enhanced ultrafast spectrometers operating from the ultraviolet to the infrared. -
Dr. Nora Kling Department of Physics, University of Connecticut, "Ultrafast Nuclear Motion: Resolving Hydrogen Migration(s) in Time", Atomic, Molecular, and Optical Physics Seminar4:00pm
11/26
Dr. Nora Kling Department of Physics, University of Connecticut, "Ultrafast Nuclear Motion: Resolving Hydrogen Migration(s) in Time", Atomic, Molecular, and Optical Physics Seminar
Monday, November 26th, 2018
04:00 PM - 05:00 PM
Storrs Campus Physics Building, P121
Dr. Nora Kling
Department of Physics,
University of Connecticut
Ultrafast Nuclear Motion: Resolving Hydrogen Migration(s) in Time
Intramolecular hydrogen migration is a natural process that plays a crucial role in many biological, chemical, and physical phenomena, and is the object of current research efforts in fuel cells, proteomics, and combustion chemistry. Using ultrafast, intense lasers and sophisticated pump-probe ion imaging techniques, we can explore the rich dynamics of hydrogen migration reactions, including what timescale they occur on. In my talk, I will present two studies. The first study is on acetylene, a small hydrocarbon, where a hydrogen can migrate across the carbon atoms to form its vinylidene isomer [1,2]. The second study is on ethanol, a complex molecule where both single and double hydrogen migrations occur, and the timescale for each is individually determined [3]. These experimental results, in combination with state-of-the art quantum chemical trajectory calculations, give us new insight into the complex nuclear motions in complex polyatomic molecules.
[1] C. Burger et al. Faraday Discussions 194, 495 (2016).
[2] M. Kübel et al. Phys. Rev. Lett. 116, 193001 (2016).
[3] N. G. Kling et al. submitted for publication -
Dr. Aaron LaForge, Department of Physics, University of Connecticut, "Excitation dynamics in helium nanodroplets induced by XUV radiation", Atomic, Molecular, and Optical Physics Seminar2:00pm
11/1
Dr. Aaron LaForge, Department of Physics, University of Connecticut, "Excitation dynamics in helium nanodroplets induced by XUV radiation", Atomic, Molecular, and Optical Physics Seminar
Thursday, November 1st, 2018
02:00 PM - 03:00 PM
Storrs Campus Gant West Building (aka Physics Building), GW121
Dr. Aaron LaForge, Department of Physics, University of Connecticut
Excitation dynamics in helium nanodroplets induced by XUV radiation
As opposed to purely molecular systems where electron dynamics proceed only through intramolecular processes, weakly-bound complexes like helium nanodroplets offer an environment where local excitations can interact with neighboring molecules leading to new intermolecular relaxation mechanisms. Here, we present a systematic, time-resolved study of the excitation dynamics when helium nanodroplets are resonantly excited by XUV free electron laser radiation. At low pulse energy, a single atom is excited leading to the formation of a bubble state which relaxes to the droplet surface on a femtosecond timescale. At high pulse energy, a network of excited atoms is formed within a nanodroplets which then collectively autoionizes with high efficiency. Using the pump-probe technique, we were able to time resolve this process. -
Dr. Shimshon Kallush, Physics and Optical Engineering Department, ORT Braude College, Karmiel, and The Fritz Haber Center for Molecular Dynamics, The Hebrew University, Jerusalem, Israel, "Molecular alignment in hot and cold regimes, and its relationship to quantum coherence", Atomic, Molecular, and Optical Physics Seminar4:00pm
9/17
Dr. Shimshon Kallush, Physics and Optical Engineering Department, ORT Braude College, Karmiel, and The Fritz Haber Center for Molecular Dynamics, The Hebrew University, Jerusalem, Israel, "Molecular alignment in hot and cold regimes, and its relationship to quantum coherence", Atomic, Molecular, and Optical Physics Seminar
Monday, September 17th, 2018
04:00 PM - 05:00 PM
Storrs Campus Physics Building, P121
Dr. Shimshon Kallush, Physics and Optical Engineering Department, ORT Braude College, Karmiel, and The Fritz Haber Center for Molecular Dynamics, The Hebrew University, Jerusalem, Israel
Molecular alignment in hot and cold regimes, and its relationship to quantum coherence
The phenomena of field-free instantaneous quantum revivals of molecular alignment and orientation driven by optical and/or terahertz fields will be introduced. A brief survey over a few applications of the phenomena will be presented within this context:
1. Ultracold photoassociation will be shown to intrinsically contain molecular alignment. Its characteristics and the feasibility to detect directional preferences for the photoassociated species will be discussed.
2. Rotational echoes of alignment under multiple pulses will be shown to lead to unique spatial-temporal structures of the refractive index. Several applications of this feature will be suggested.
3. The quantum picture of alignment raises questions that relate to the ability to embed quantum coherences into thermal quantum systems. The problem of quantification of coherences is defined and some results that predict the ability to induce field-driven coherences will be presented