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Physics Graduate Projects at UT Space Institute

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Title: Physics Graduate Projects at UT Space Institute


1
Physics Graduate Projects at UT Space Institute
  • Professor Horace Crater
  • Professor Lloyd Davis
  • Associate Professor Christian Parigger
  • Research Assistant Professor Ying Ling Chen
  • Emeritus Professor Jim Lewis
  • Adjunct Professor Charles Johnson
  • Center for Laser Applications
  • www.utsi.edu/ldavis ldavis_at_utsi.edu

UTSI
Physics 599 seminar class UT Knoxville, November
11, 2009
2
Where is. ?
3
Where is. ?
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Where is. ?
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University of Tennessee Space Institute
  • UTSI is a graduate campus of the UT Knoxville
  • Graduate students may transfer between the
    campuses
  • Students at UTSI obtain MS and PhD degrees from
    the University of Tennessee Knoxville
  • Same degree requirements at UTSI and UTK
  • UTSI has GRA positions, but no TA positions
  • UTSI physics common practices
  • PhD students have a committee member based in
    Knoxville
  • Most students complete the MS degree en route to
    the PhD
  • Some classes are offered at both campuses by
    interactive distance education
  • Phys. 513, 514 606, 610, 643

9
University of Tennessee Space Institute
  • GRA and thesis/dissertation physics research
    opportunities are available
  • with the Center for Laser Applications
  • with research groups at the Air Force
    Arnold Engineering
    Development Center
  • and in selected areas of theoretical particle
    physics
  • Opportunities are also available for
    interdisciplinary research in Materials Science
  • Solid state / materials physics

10
Theoretical Particle Physics with Professor
Horace W. Crater
  • Relativistic Two-Body Dirac Equations
  • Meson Spectroscopy and Decays
  • Bound and Scattering States in Quantum
    Electrodynamics
  • Nucleon Nucleon Scattering
  • Bound States in Quark-Gluon Plasma
  • Relativistic N-Body Problem Plus Fields
  • Electrodynamics, General Relativity
  • Relativistic Center of Mass

Matthew Duran-MS Physics, 2007 Modeling the
ground-state Baryon octet using a generalization
of the Lagrange triangle solution
11
Kyle Peterson-PhD Physics, December
2003 Computational magnetohydrodynamic
investigation of flux compression and implosion
dynamics in a Z-pinch plasma with an azimuthally
opposed magnetic field configuration electronic
resource Karen Norton-MS Physics, August
2006 Ultraviolet image analysis of spacecraft
exhaust plumes
12
Jesse Labello - MS Physics, 2007 Characterization
of the temperature dependence of optical
components in the 10V cryo-vacuum chamber
Howard Frederick MS Physics,
2008 Experimental determination of emissivity
and resistivity of Yttria stabilized Zirconia at
high temperatures
13
University of Tennessee Space Institute Center
for Laser Applications
CLA lab
Tennessee Higher Education Commission Center of
Excellence
14
Laser Spectroscopy with
Professor Christian Parigger
  • Laser-induced breakdown spectroscopy
  • Atomic and molecular spectroscopy
  • Computational
    modeling of

    laser breakdown
    phenomena

Pavlina J. Jeleva-PhD Physics, 2005 Photo-acousti
c analysis of dental materials and tissue
15
Research Interests Professor Lloyd M. Davis
  • Single-molecule spectroscopy, nanophotonics,
    biophotonics, biophysics, chemical physics
  • Non-linear optics, quantum optics, ultrafast
    spectroscopy
  • Femtosecond laser material and laser plasma
    interactions
  • Numerical physics, Monte Carlo simulations

David Ball-PhD Physics, December
2006 Single-molecule detection with active
control
  • Present position Postdoctoral fellow,
    Virginia
    Bioinformatics Center, 5-yr NIH funding

16
Davis GRA Students (spring 08)
  • Justin Crawford
  • You Li
  • Jason King
  • James Germann
  • Jesse Ogle (AEDC)
  • Will Robinson
  • Isaac Lescano (EE)

Larissa Wenren
17
Outreach OSA student chapter
18
Single-molecule detection in solution was first
achieved
by using pulsed laser excitation and time-gated
photon counting to reject the Raman scatter that
overlaps the fluorescence band
19
Maximum likelihood data analysis
Measurements with small numbers of photons Eg.,
Fluorescence Lifetime of a single molecule
Find ? such that Prob(Data ? ) is a maximum
Error in lifetime ? ? ? number of photons
Least-squares curve fitting fails because it
assumes a Gaussian distribution of errors
20
Maximum-likelihood multi-channel photon-counting
microscopy
Justin Crawford
count-rate dependent time-walk
We have improved the sensitivity of time and
spectrally-resolved imaging for applications that
require resolving the signal contributions from
fluorescent species with overlapping spectra
NIH/NIBIB R03 grant
New MPD Modified Module
21
High-throughput modular microfluidic systems for
drug discovery/development
  • NIH R01-grant 2007-2011
  • Collaborators Louisiana State University, Tulane
    University
  • UTSI
  • Develop of a set of ultra-sensitive near-infrared
    fluorescence readout methods for determining
    molecular species concentrations within plastic
    (PMMA) microfluidic devices
  • Goal is to determine changes in enzyme activity
    in response to a library of 100,000 compounds
  • Parallelized assays of enzyme activity with
    nanoliter samples by use of CCD camera
  • Demonstrate the developed platform by searching
    for inhibitors of L1-endonuclease, an enzyme
    implicated in cancer

22
Use of diode laser for detection of near-infrared
phthalocyanine dyes
You Li
Raman notch transmission
We are developing custom instrumentation for
ultrasensitive detection of deep-red fluorophores
for application to pharmaceutical drug screening
within PMMA microfluidic devices.
23
You Li Photon bursts from single near-ir dye
molecules
24
Single Protein Studies
25
Single-molecule detection in a nanochannel
  • Goal
  • To detect and trap single molecules of
    fluorescently-labeled proteins in solution with
    high photon count rate for studies of protein
    interactions and conformational changes with time
    resolution of tens of microseconds
  • Approach
  • Confocal fluorescence microscope
  • Confine molecules in nanofluidic channel
  • Custom electronics to actively
    control
    electrokinetic transport

    for positioning each molecule in
    confocal
    volume
  • Excite fluorophore to saturation
    using intense
    laser
  • Replace molecule after bleaching

26
Nanofluidics fabrication strategies
  • Approach 1 EBL/RIE Nanochannels and Bonding
  • Electron Beam Lithography
  • Photolithography
  • Bonding with Fused-Silica
  • Approach 2 Sacrificial Nanochannels and Bonding
  • Electron Beam Lithography
  • Wet Etching of Sacrificial Lines
  • Approach 3 FIB Machining and Bonding
  • Focused Ion Beam
  • Bonding with Fused-Silica
  • Approach 4 Femtosecond Laser Direct Writing
  • High-Aspect Vertical Nanoholes
  • Possibility of enhanced light collection from

    a single molecule in a vertical nanochannel

27
Single microjoule femtosecond laser-pulse
fabrication of 10-micron deep nano-holes
photodiode
ultrafast mirror
3D piezo
  • Nikon CF Plan Achromat 79173
  • 150 mm conjugate
  • Dry, NA 0.85, WD 0.410.45 mm
  • cc for 0.110.22 mm, n 1.52

28
Depth measure by SEM/FIB sectioning
Cross-section near top of holes
  • Use of the DualBeam? SEM/FIB tool, CNMS, ORNL
  • Diameters of 200-500 nm and depths exceeding 11
    micron

29
Possible mechanisms for high aspect holes
  • Creation of similar long features internal to the
    material has been attributed to
  • self-focusing due to Kerr nonlinearity of fused
    silica EN Glezer E Mazur, Appl. Phys. Lett.
    71, 882884 (1997)
  • interface-induced spherical aberration
    self-focusing
    Q Sun, et
    al., J. Opt. A Pure Appl. Opt. 7, 655659
    (2005)
  • long features only when gt 20 µm from the surface
  • Focusing with spherical aberration
  • objective correction collar for 0.110.22 mm, n
    1.52

Air SiO2
cc.17
Zemax
30
Possible mechanisms for high aspect holes
  • Creation of similar long features internal to the
    material has been attributed to
  • self-focusing due to Kerr nonlinearity of fused
    silica EN Glezer E
    Mazur, Appl. Phys. Lett. 71, 882884 (1997)
  • interface-induced spherical aberration
    self-focusing
    Q Sun, et
    al., J. Opt. A Pure Appl. Opt. 7, 655659
    (2005)
  • long features only when gt 20 µm from the surface
  • Focusing with spherical aberration
  • objective correction collar for 0.110.22 mm, n
    1.52

Zemax
Single-pulse ultrafast-laser machining of high
aspect nano-holes at the surface of SiO2,
YV White X Li Z Sikorski LM Davis W
Hofmeister, Optics Express 16, 1441114420 (2008).
31
Nanofluidic device fabrication
microchannels
4 inch, 500 mm SiO2 wafer
UV
nanochannels
coat 3 mm
e-beam
exposure
UV resist
exposure
develop
PMMA
50 nm
etch
develop
chrome
50 nm
reactive ion etch
SiO2
etch
cleaning CO2 laser hole punching wafer
dicing cleaning cover slip bonding
reactive ion etch ? PMMA removed
32
Bonding of patterned chips
To avoid nanochannel collapse Low temperature
bonding lt100 ?C Surface cleaning in HF
solution Pressure1MPa Bonding time 12 hours
33
SEM characterization of nanochannels
Dual Beam FIB/SEM
34
Assembled nanofluidic device
electrodes
Plexiglass housing
nanofluidic chip
aluminum base
laser
35
1-D trap in a nanochannel
Irradiance profile
  • Molecules are confined to 1-D within 100 nm
    nanochannel
  • Two displaced laser beam foci pulse-interleaved
    excitation
  • Irradiance at center constant
  • Time-gated photon detection
  • Electrophoretic/electro-osmotic motion along the
    nanochannel

V2
nanochannel
immersion fluid
V1
V
microscope objective
nanochannel
laser
36
The Laboratory
37
Control of electrokinetic voltage
nanofluidic device
sync
1.2 NA objective
beam dump
pump laser 76 MHz 608 nm two beams, each 30 mW
with 6.6 ns delay
filters
custom FPGA board
sliding mirror
I-MAX ICCD camera
pinhole
NI PCI-6602 counter / timer
SPAD
38
Numerical simulations of single-molecule trapping
William N. Robinson
First molecule enters at 70.8 ms
Molecule photobleaches
Laser beam positions 0.3 µm
Expected duration of capture before bleaching
(?10?5)
39
Fluorescence autocorrelation
15 s
Nanochannel freshly loaded with 0.6 pM
streptavidin/Alexa 610 in 0.2 PBS
active electrokinetic control
?10 V
0 V
FPGA voltages seen on oscilloscope during trapping
40
Other ongoing projects
  • Single-Molecule Trapping
  • 1-D in nano-fluidic device
  • 3-D in micro-fluidic device
  • Single-Molecule Tracking

41
4-Foci Fluorescence Microscope and Maximum
Likelihood Analysis
James Germann
Confocal microscope with 4 beams focused in
tetrahedon provides sub-micron position
trajectory information
42
Microfluidic device for 3-D electrophoretic trap
Jason K. King
Platinum coated coverslip

-
Configuration 2.5V, 10mA
-

43
Further information
  • Contact ldavis_at_utsi.edu
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