enlightened by lasers q. charles su intense laser physics theory unit illinois state university cas...
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Enlightened by lasersQ. Charles Su
Intense Laser Physics Theory UnitIllinois State University
CAS Lecture 2006 Illinois State University April 25, 2006
SupportNational Science Foundation
US Department of EnergyResearch Corporation
College of Arts & SciencesDepartment of Physics
LightNewton, Edison (1879) lights up Manhattan (1882)
Laser usagesCD writer, player, laser pointer, scanner, light knife, cosmetic treatment, laser show
What’s in a laseractive medium, stimulated emission, resonatorMaiman, Townes, MIT echo off moon
Probing matter with lasersIonization process, world mapMedical imaging, patentMatter creation, Klein
Research vs educationILP approach
In the beginning there was no light …
fire makes us happy
IN THE BEGINNING - (c 4.5 Billion BC)THE SUN - (c 4 Billion BC)THE EARTH - (c 4 Billion BC)EARLY LIFE - (c 3 Billion BC)PHOTOSYNTHESIS - (c 2 Billion BC)FIRST MAN - (c 1 Million BC)EARLY MAN - (c 500,000 BC)FIRE, FLAME and TORCH - (c 400,000 BC)PRIMITIVE LAMPS - (c 13,000 BC)ANIMAL LAMPS - (c 5000 BC)EARLY LIGHTING - (3000 BC)SUNDIAL - (c 1500 BC)OIL POTTERY LAMPS - GREEK - (600 BC)OIL RESERVOIR LAMP - (500 BC)ROMAN - LIFE & LIGHT - (400 BC - 80 AD)COLOR AND MUSIC (SOUND) - (c 350 BC)EARLY OPTICS & LENSES - (c 300 BC)HORN LANTERN - (c 100 AD)CANDLE - (c 400)CAMERA OBSCURA - (c 1000)COLORS OF THE SPECTRUM - (1666)POLARIZATION/POLARIZED LIGHT - (1678)PHOTOGRAPHY, EARLY - (1727)ADDITIVE COLOR MIXING - (1769)BETTY LAMP (& BETSY LAMP) - (1790)FIRST - GAS LIGHTING - (1792)INFRARED - (c 1800)
ULTRAVIOLET LIGHT (UV) - (1801) ELECTRIC ARC LIGHT/ CARBON ARC LIGHT - (1809)PHOTOGRAPHY, MODERN - (1826)SPEED OF LIGHT - (1849)SPECTROSCOPE - (c 1850) KEROSENE LAMP - (1853)FIRST - FOLLOWSPOT SPOTLIGHT - (c 1856)PHOTOGRAPHY, MOTION PICTURES - EARLY - (1872)FIRST - ELECTRIC FILAMENT (INCANDESCENT) LAMP - (1874)EDISON LAMP - (1879) SWAN LAMP - (1879)FIRST - PHOTOCELL - (1880)ELECTRICITY - (1899)HIGH INTENSITY DISCHARGE (HID) LAMP - (1901)MERCURY-VAPOR LAMP - (1901)TUNGSTEN FILAMENT LAMP - (1907)GAS FILLED LAMP - (1913)FLASHBULB - (1930)SODIUM LAMP - (LOW PRESSURE) - (1932)FLUORESCENT LAMP - (1937)PHOTOGRAPHY - POLAROID CAMERA - (1947)FIBER OPTICS - (1955)LASER - (1960)HOLOGRAM/HOLOGRAPHY - (a 1960)QUARTZ HALOGEN LAMP - (1960)LIGHT EMITTING DIODE - (a 1965)
A very brief history of light
wave theory
corpuscular theory
Christiaan Huygens1629–1695
James Clerk Maxwell1831–1879
Sir Isaac Newton1643 –1727
Electromagnetic waves
Albert Einstein 1879–1955
photons
Theories of light
laying of the mains and installation of the world's first permanent, commercial centralpower system in lower Manhattan, which became operative in September 1882.
Edison practically lit up the world
LightNewton, Edison lights (1879) up Manhattan (1882)
Laser usagesCD writer, player, laser pointer, scanner, light knife, cosmetic treatment, laser show
What’s in a laseractive medium, stimulated emission, resonatorMaiman, Townes, MIT echo off moon
Probing matter with lasersIonization process, world mapMedical imaging, patentMatter creation, Klein
Research vs educationILP approach
Laser usagesprecision
CD playerscannerprinter
powercutting, laser surgery
temporal precisionprobe fast processes
high temperaturefusionphotodynamic therapy
cheaper / safer imagingphoto density waves
In the movies
Laser shows
LightNewton, Edison lights (1879) up Manhattan (1882)
Laser usagesCD writer, player, laser pointer, scanner, light knife, cosmetic treatment, laser show
What’s in a laseractive medium, stimulated emission, resonatorMaiman, Townes, MIT echo off moon
Probing matter with lasersIonization process, world mapMedical imaging, patentMatter creation, Klein
Research vs educationILP approach
Active medium (hurdles in a stadium)
Hurdles ~ Atoms
Hurdle in up position~ population inversion
Hurdle reset after fall down~ external “pumping”
A hurdle goes down, energy releases, a pigeon flies away
pigeon ~ photon
down randomly~ spontaneous emission of light
After many hurdles are down …
No laser
Now a pigeon with the right energy knocks down a hurdle…
+ = hurdle is down +
2 pigeons fly off exactly the same way
~ stimulated emission of light (Einstein)
2 4 8 16 32 64 128 256 512 1024 2048 4096 8192 16384 32768
… (after 29 rounds) 536,870,912 > US population… (after 33 rounds) 8,589,934,592 > world population
all in concert with each other
~ light amplification
Start with one pigeon
Let pigeons turn around in the stadium and work hard…
Then open up the stadium gate from time to time~ Light Amplification by Stimulated Emission of Radiation
Ingredients of a laser(1) Active medium with population inversion(2) Stimulated emission(3) Light amplification with resonator
LightNewton, Edison lights (1879) up Manhattan (1882)
Laser usagesCD writer, player, laser pointer, scanner, light knife, cosmetic treatment, laser show
What’s in a laseractive medium, stimulated emission, resonatorMaiman, Townes, MIT echo off moon
Probing matter with lasersIonization process, world mapMedical imaging, patentMatter creation, Klein
Research vs educationILP approach
Laser laboratories and how they are related to my research
Lab for Laser Energetics (U. Rochester)Laser fusion experiments Diagnostics temperature and density determinations x-ray imagingISU-UR collaboration through the DOE NLUF grants
Intense laser facilities around the worldSaclay-France FOM-Holland MPQ-Germany Lund-SwedenSIOFM-China U Tokyo-Japan QOLS-UK URC-CanadaATT BrookHaven U Michigan LLLISU: Numerical/Gedanken experiments
Ultra relativistic laser experiments planedDESY, Hamburg GSI-DarmstadtSLAC-Stanford CUOS-Ann ArborISU: Computer simulations, NSF grants
Bio-optical imaging researchLabs: U Penn, UC Irvine, U Mass, UIISU: light scattering lab and MC computations
Modeling laser action on computers
Physics andequations
Computerprogramming
Simulations ofexperiments
Result visualization Explanation More simulations
Great space for (undergraduate) student involvement
ˆ b p(t) ˆ b p' p U(t) p' p' ˆ d n'
p U(t) n'n'
ˆ d n(t) ˆ b p' n U(t) p'
p' ˆ d n'
n U(t) n'n'
ˆ b p(t)Wp(x) p ˆ d n
(t)Wn(x)nx,t̂
U(t)=T exp{–i∫0t dt’ [c·p–·A(x,t’)+c2+V(x,t’)]}
Laboratory experiments guide theoryMultiphoton ionization 1960sAbove threshold ionization 1979–Higher order harmonic generation 1980s
Computer experiments predict new physics?Atomic stabilization 1990 Cycloatom 2000Klein paradox 2004Bioimaging 2005
Fishing or cleaning fish ?
Laser atom
+–
+ –+
–
Laser-atom interaction
A microscopic view
Outcome 1: bound Outcome 2: ionized
How does ionization vary with laser intensity ?QuickTime™ and a
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V(x) 1/ 1 x2
J. Javanainen, J.H. Eberly and Q. SuPhys. Rev. A 38, 3430 (1988)
Computer simulation of atomic ionization
Pick a laser intensity I
Model atom (Rochester model)
Interaction with laser
Solve: Schrödinger equation
Compute ionization for each state
Current QM state future state
Gedanken experiment on computer:Ionization beyond 1016 W/cm2
ionization
100%
0 laser intensity
?IN
weak
all ionized
strong
superstrong
10–6
10–4
LASER
INTENSITY
P(t)
P(t)
P(t)
P(t)
P(t)
P(t)
P(t)
P(t)
I1
I3
I2
I4
I4
I5
I6
I7
Su, Eberly, Javanainen PRL, 64, 862, ’90
10 -1
10 0
10 -2 10 0 10 2
P(T,
I)
I (a.u.)
1st recovery
2nd3rd
Ioni
zati
on P
(T)
Laser intensity, I
123
4 56
7
Ionization Suppression!
I > 1016 W/cm2
Electron spatial density
Su, Laser Phys. 3, 241 (1993)Gavrila, Atoms in Intense Fields (1992)
Las
er in
tens
ity
space0
atom Outcome 1: bound + –
stabilization+ –Outcome 3:
stabilized
ionization+
–Outcome 2:
ionized
Computer prediction: Stabilization
NormallyIncreased intensity increases ionizationmore chance for electron to pick up energy around nucleus
At super-strong fieldsLaser also distorts electron orbitsreduces the chance of interaction with nucleus
Other theoretical studies and experimental evidenceKulander et al, Atoms in Intense Laser Fields Ed Gavrila, (1992)Keitel and Knight, Phys. Rev. A 51,1420 (1995)van Druten, et al Phys. Rev. A 55 622(1997)Longhi, et al, Phys. Rev. Lett. 94, 073002 (2005)
+ –
+ –
10 -1
10 0
10 -2 10 0 10 2
P(T
, I)
I (a.u.)
1st recovery
2nd3rd
n = S
S
Stabilization and recoveries of ionization
Su, Irving*, Johnson*, Eberly, J. Phys. B 29, 5755 (1996)Su, Irving*, Eberly, Laser Phys. 7, 568 (1997)
> 128 groups in 23 countries
Users of the Rochester model atom
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LightNewton, Edison lights (1879) up Manhattan (1882)
Laser usagesCD writer, player, laser pointer, scanner, light knife, cosmetic treatment, laser show
What’s in a laseractive medium, stimulated emission, resonatorMaiman, Townes, MIT echo off moon
Probing matter with lasersIonization process, world mapMedical imaging, patentMatter creation, Klein
Research vs educationILP approach
safer than x-ray CTcheaper than MRIbetter resolved than ultrasound
Dream: to build an imaging device …
Possible solution: IR laser based imaging
Imaging schemes
shadowx-ray
shadow-gram (like x-ray, CAT)
reflection-gram (like ultra-sound)
scatter-gram (infrared lasers)
ultra-sound
laser
medium —> scattered light
medium <— scattered light
Forward problems (predict the future)
Inverse problems (predict the past)
Light-medium interaction computer simulations
Pane of glass Random medium
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FFT on the grid method Wanare, Su and Grobe, PRE 62, 8705 (2000)
X-rays vs laser light
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Monte Carlo Simulation S. L. Jacques and L.-H. Wang, in Optical Thermal Response of Laser Irradiated Tissue, edited by A. J. Welch and M. J. C. van Gemert (Plenum Press, New York, 1995), pp. 73-100.
Complication of laser-based image reconstruction
• X-ray
• Laser
Modulation of light induces beam narrowing
= 0
0
wide beam
narrow beam
Transverse light beam waist
Pulse width shrinks with increasing frequency
Distance fromoptical axis
Intensity I
ISU filed patent application in 2005
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Beyond theory: experiment?
InputLaser
OutputFiber z
Laboratory measurements for on axis light intensityS. Campbell, A. O’Connell, S. Menon, Q. Su and R. Grobe, PRE, submitted
0
4
8
0 10 20 30 40z [cm]
Log
(N)
experiment
simulation
theory I
theory II
-0.6 -0.4 -0.2 0 0.2 0.4 0.6
2
4
6
8
y [cm]
z=0cm
z=10cm
z=5cm
LightNewton, Edison lights (1879) up Manhattan (1882)
Laser usagesCD writer, player, laser pointer, scanner, light knife, cosmetic treatment, laser show
What’s in a laseractive medium, stimulated emission, resonatorMaiman, Townes, MIT echo off moon
Probing matter with lasersIonization process, world mapMedical imaging, patentMatter creation, Klein
Research vs educationILP approach
Matter creation from light?
E = mc2
Light = electron + positron
Mourou, Yanovsky
Opt. Ph. News 15, 40 (2004)
1026Laser intensity >
“Conjuring matter from light”Science, Aug, 29, 1997
“Real photons create matter”Physics News, Sept. 18, 1997
“Light work”New Scientist, Sept. 27, 1997
“Boom! From light comes matter”Photonics Spectra, Nov. 1997
“Matter from light”CERN Courier, Nov. 1997
“E=mc2, really”Scientific American, Dec. 1997
“Let there be matter”Discover, Dec. 1997
“Gamma rays create matter by plowing into laser light”Phys. Today, Feb 1998
Popular science articles on matter creation from light
Wave or particle description of matter ?
Traditional wave viewDirac Equation (1928)deals with physics after creation (no creation)
Particle viewQuantum Field Theory (1940s)deals with # of creation(no wave nature)
Computational QFTPhys. Rev. Lett. (2004) wave nature during creation(new framework)
?????????????
Man
y bod
y quan
tum
field
theo
ry
What are these nice graphs?
From quantum field theory to quantum mechanics
it x,t= [ c ·p–·A+c2+V ] x,t
(x,y,t) = <0|| (+)(x,t) c(+)(y,t) || (t=0)>
vacuumstate
positivefrequency
part
chargeconjugation
initialstate
S.S. Schweber, “An introduction to relativistic quantum field theory”
Krekora, Su, Grobe, PRL 92, 040406 (2004) ; PRL 93, 043004 (2004)Braun, Su, Grobe, PRA 59, 604 (1999)
C.H. Keitel, Cont. Phys. 42, 353 (2001)A.D. Bandrauk, H. Shen J. Phys. A, 7147 (1994)
Solution of the field operator for e– and e+
ˆ b p(t) ˆ b p' p U(t) p' p' ˆ d n'
p U(t) n'n' ˆ d n
(t) ˆ b p' n U(t) p' p' ˆ d n'
n U(t) n'n'
Dirac equation for field
Solution whereˆ b p(t)Wp(x) p ˆ d n
(t)Wn(x)nx,t
U(t)=T exp{–i∫0t dt’ [c·p–·A(x,t’)+c2+V(x,t’)]}
ˆ
ˆ
ˆ
ˆ
ˆ
Of course!
Now everything makes sense!
The space-time resolved pair creation
e– e+
energy
Sample projects that employed the new CQFT method
(1) Space time resolved pair creation
(2) Klein paradox, 70 years old
Phys. Rev. Lett. 92, 040406 (2004)
Phys. Rev. A 72, 064103 (2005)
(3) Localization and Zitterbewegung
Phys. Rev. Lett. 93, 043004 (2004)
(4) Entanglement
J. Mod. Opt. 52, 489 (2005)
(5) Modified Schwinger formula
Las. Phys. 15, 282 (2005)
(6) Supercritical bound states
Phys. Rev. Lett. 95, 070403 (2005)
(7) Interpretational difficulty in QED
Phys. Rev. A, 73, 022114 (2006)
Experimental verification?Time dependent colliding ions (existing)
Static supercritical field
Experimental plans:
CUOS Ann Arbor, Michigan
DESY Hamburg, Germany
GSI Darmstadt, Germany
SLAC Stanford, California
“Zeptotechnology is just around the corner”
The Economist, page 77 Feb 28 2004
Laser fields lead to new unions of
ParticleGravitational
AtomicPlasma
Astro-physicsCosmology
Zetta-watt
Zepto-seconds
Enlightened ?
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LightNewton, Edison lights (1879) up Manhattan (1882)
Laser usagesCD writer, player, laser pointer, scanner, light knife, cosmetic treatment, laser show
What’s in a laseractive medium, stimulated emission, resonatorMaiman, Townes, MIT echo off moon
Probing matter with lasersIonization process, world mapMedical imaging, patentMatter creation, Klein
Research vs educationILP approach
Graduate or Undergraduate
US, best graduate school system in the world> 50% Nobel in Science after WWII good research-industry relation
What about our pre-graduate educationCuts in education fundingFlat science fundingMath/Science not “cool” in school
Do we need to change the perception?
Large number of studentsLarge number faculty mentors National awardsShow cased at conferences
Center or Research and Education on NanostructuresCenter for Research and Instruction in Space PhysicsIntense Laser Physics Theory UnitSurface Science LabPolarized Electron LabAtomic StructureStatistical MechanicsNonlinear DynamicsMathematical Physics
Undergraduate physics research at ISU
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Undergraduate research at ILP
Our approachStart earlySmall group collaborationProject design, execution, completionKnow physics, math, programmingUse intuition, catch misconceptionCommunicate result with others
Thanks to funding agencies Big thanks to colleagues past and present
Support from CAS, RSP, Honors Program Physics faculty colleagues
Postdoctoral fellowsAll 35 undergraduate students
Especially Prof. Grobe for collaborations
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Thanks to Alex,Christina, and Jean!
Thanks for attending
and
enjoy some refreshment !
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