Group

McMorran group March 1, 2016 Front row, left to right: Fehmi Yasin, Quin Konyn (undergrad), Eryn Cangi (undergrad), Saul Propp Back row, left to right: Alice Greenberg, Tyler Harvey, Jordan Chess, Ben McMorran, Spencer Alexander, Jordan Pierce Not shown: Galen Gledhill

McMorran group March 1, 2016
Front row, left to right: Fehmi Yasin, Quin Konyn (undergrad), Eryn Cangi (undergrad), Saul Propp
Back row, left to right: Alice Greenberg, Tyler Harvey, Jordan Chess, Ben McMorran, Spencer Alexander, Jordan Pierce
Not shown: Galen Gledhill, Cameron Johnson

 

Prof. Benjamin McMorran, Principle Investigator

Assistant Professor of Physics
Oregon Center for Optical, Molecular, and Quantum Sciences
Materials Science Institute
Department of Physics

Curriculum Vitae

Google Scholar page

 

Jordan Chess

Graduate Student

My research is focused on using transmission electron microscopes (TEM) to understand magnetic materials.  As part of this work our group is developing new magnetic imaging techniques including electron vortex magnetic chiral dichroism, which is expected to be capable of producing atomic resolution spin maps, and relies on measuring the difference in inelastic scattering rate for electron beams with opposite orbital angular momentum. In addition to working on new techniques I also use a well established technique Fresnel contrast Lorentz TEM, to image skyrmion materials. LTEM takes advantage of the fact that electrons passing through a magnetic field pick up a phase shift due to the Aharonov-Bohm effect, by examining defocused images of these samples we can gain qualitative information about the magnetic state of the sample such as the location of domain walls, and direction of the domains on either side of the domain walls. In addition to this qualitative information I also use transport-of-intensity (TIE) and/or iterative wave reconstruction techniques applied to images taken at multiple defocus values to determine the phase of the electron wave function exiting the sample from this phase we can quantitatively determine the local magnetic field times the thickness of the sample, like that shown below.

LTEM_SITIE

View Jordan’s webpage

NoPhoto

Galen Gledhill

Graduate Student

As a member of the McMorran group I am investigating charged particle optics and beam physics including orbital angular momentum effects. I have a strong background in computational physics and use this as a complement to my experimental work. Concurrent with my University of Oregon research I am a scientist at FEI company in the FIB technology group.

NoPhoto

Alice Greenberg

Graduate Student

I am interested in the parallels between physical optics and the electron phenomena that Ben McMorran studies. In particular, I want to explore interesting beam modes, such as Hermite-Gaussian and Laguerre-Gaussian modes, and their potential applications. Most of my experience is in optics; in the past I have developed optical systems for a scanning tunneling microscope and the electron spectrometer of the KATRIN experiment. Similarly, I am interested in projects developing new optical and electron wave techniques and systems.

 

Cameron_picture-3283

Cameron Johnson

Graduate Student

I am a second year graduate student with a background in using optics to study point defects in semiconductors. I am interested in studying the interaction of electron vortex beams with matter using energy loss spectroscopy. However, poor beam quality and the low signal to noise ratio of current spectroscopic studies with electron vortex beams have hindered progress in the field. As a result, I have been focused on pursuing different nanofabrication methods to create forked electron diffraction gratings which produce high quality electron vortex beams with a sufficient intensity to perform spectroscopic studies.

Jordan Pierce

Graduate Student
Project: Electron Spin-to-Orbital Angular Momentum Transfer

My primary work is to develop methods and procedures for manufacturing high quality electron diffraction gratings.  Within a Transmission Electron Microscope (TEM), direct control of the transverse beam profile is quite difficult, and traditional TEM regimes seek to have the beam be as plane-wave as possible, limited only by the diffraction through the selecting aperture.  Directly controlling the beam profile with electromagnetic lenses is expensive and limited to only the lowest few modes.  By utilizing diffractive holograms in the beam column, a wide variety of beam profiles are allowed and can be easily created.  However, the process of diffracting an electron beam through a hologram brings with it a number of disadvantages, such as that the diffracted beams are not aligned with the same optical axis as the incident beam, that the energy spread might increase and coherence length decrease, that the intensity in diffracted orders is lowered, and so on.  Thus, designing a grating which minimizes the disadvantages and maximizes the utility for a particular application is necessary.

Currently I am focusing on creating ‘apodized gratings’ which have spatially varying diffraction efficiency to better recreate pure modes (such as Laguerre Gaussian or Hermite Gaussian).  Future work will be increasing the reliability and scalability of the production process while still improving on diffraction efficiency and beam quality.  Below is an example of a binary amplitude fork dislocation grating.  The fork dislocation produces beams which have an integer multiple of hbar orbital angular momentum in the diffracted orders.

NoPhoto

Saul Propp

Graduate Student

I am interested in exploring potential applications of electron vortices for particle physics experiments. I hope to use GPT to simulate electron vortex beams propagating through the various elements (boosters, focusing lenses, storage rings, etc…) needed in high energy experiment, particularly focusing on application for electron vortices for plasma wakefield acceleration (a novel and highly-promising method of accelerating electrons for use in linear colliders). Additionally, I am interested in the relationship between electron vortices and electron zitterbewegung (a rapid oscillation associated with electron spin). Recent analysis of zitterbewegung using geometric/spacetime algebra have provided insight into the structure of the phenomena, and I hope to use to the tool to describe electron vortices as well. Zitterbewegung is also highly related to the effect of spin-orbit coupling, which is relevant both for electron vortices in general and in particular, their use in particle accelerators. A recent high energy experiment probed electron zitterbewegung for the first time, and I hope to at some point to help follow-up this experiment using electron vortices to further explore zitterbewegung.

Fehmi Yasin

Graduate Student
Project: STEM Holography, Development of an Electron Interferometer

My research is focused on using transmission electron microscopes (TEM) in scanning (STEM) mode to perform electron interferometry experiments. As part of this work our group developed a new technique we call STEM-holography (see figure below), inspired by J.M. Cowley. In addition to working on this technique on the microscope, I spend many hours optimizing the theory and phase reconstruction code for two and three electron beam interference experiments. I will be continuing the development of this technique with Hitachi at their Central Research Laboratory in Hatoyama, Japan next year.

I was lucky enough to teach for my first two years of graduate school, both as a Graduate Employee and a Science Literacy Program (SLP) Fellow. As the latter, I worked with Dr. Ben McMorran to develop curricula and syllabus for a progressive version of PHYS 252-3. We worked towards incorporating a more active learning style during lecture and tutorials via clickers and updated worksheets. I also helped to develop at least half of the exam questions for each exam. Teaching matters!

Additionally, I have developed and coordinated Mad Duck Physics. Since 2014, multiple undergraduate students in the Society of Physics Students (SPS) as well as graduate student volunteers and I have been commuting to River Road Elementary School once a month during their school year to perform hands-on physics and chemistry demos with the students there (usually 3rd through 5th grade). These visits culminate in a field trip that they take to the University of Oregon Physics building, where we perform larger demo shows in addition to smaller hands-on demo stations. Please email me if you’d like to get involved!

stemh

 

 

Former Visitors

vincenzo_grillo_2_400

Vincenzo Grillo

Adjunct Research Associate

Former Lab Members

Spencer Alexander

Graduate Student

Currently: PhD Student, Wang Group, Department of Physics, University of Oregon

NoPhoto

Nick Anthony

Graduate Student

HarveyTyler

Tyler Harvey

Former Graduate Student

Currently: Postdoc, Ropers Group, Physical Institute, Georg-August-Universitat Goettingen

NoPhoto

Brian Perrett

Undergraduate Student

NoPhoto

Jon Ruffin

Former Graduate Student

Rudy Resch

Graduate Student

Currently: PhD Student, Alemán Group, Department of Physics, University of Oregon

Schachtner

Alex Schachtner

Former Undergraduate Researcher

Currently: Graduate Student, Department of Physics, University of Florida

NoPhotoLady

Eryn Cangi

Undergraduate Student

 

NoPhoto

Simon Swifter

Undergraduate Student

NoPhoto

Michael Womack

Undergraduate Student

 

Dave Shook

Former Master’s Student

Currently: Applications Development Engineer (Intern) at FEI Company

 

NoPhotoLady

Jenna Wardini

Former Master’s Student

Currently: Applications Development Engineer (Intern) at FEI Company

Carly Wright

Former Undergraduate Researcher

Currently: Optical Engineering Intern, Northrop Grumman Aerospace Systems

Tyler Yahn

Former Graduate Student

Currently: Senior System Engineer at Urban Airship

 

Summer Lab Students

Bisola Fatunbi

REU Student (Lincoln University)

Malia Kawamura

NSF REU Student (Colby College and Dartmouth College)

Currently: Graduate Research Assistant at University of Illinois at Urbana-Champaign