PHYS 599B: Optics, Spectroscopy, Ultrafast Laser · PHYS 599B: Optics, Spectroscopy, Ultrafast Laser Phenomena • Who: beginning

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  • PHYS 599B: Optics, Spectroscopy, PHYS 599B: Optics, Spectroscopy, Ultrafast Laser PhenomenaUltrafast Laser Phenomena

    Who: beginning researchers in science and engineering with introductory quantum mechanics and solid state physics/chemistry who are interested in lasers, ultrafast laser science and technology, nonlinear optics, nanoscale science and correlated electron systems

    Course philosophy: key concepts/models, techniques and understandingsstart from scratch & Introduce concepts as they appeargain insights into diverse spectroscopy techniques and data analysis methodsmaster a non-sequential way of learning fill understanding gaps in some research sub-fields difficulty: classical semi-classical fully quantized

    J. Wang

  • Course formatCourse formatLectures, short seminars & discussionsLectures, short seminars & discussions

    1:10 3:00 every Tuesday

    Lecture (50 minutes) by J. Wang

    Break (10 minutes)

    Presentation #1 (25 minutes) (10 minutes) + discussion (10-15 minutes)

    Presentation #2 (25 minutes) (10 minutes) + discussion (10-15 minutes)

  • Things we will be talking aboutThings we will be talking aboutLight sources and tools, science/technology enabledLight sources and tools, science/technology enabled

    1st week General discussion on this course, timescales, order of magnitude, atoms, photons and solids, lasers

    2nd week Overview: linear and nonlinear optics, ultrafast science and technology, time-resolved spectroscopy

    3rd week Basic optics and light-matter interaction (I): optical susceptibilities, refraction and absorption, dipole oscillator model of a solid

    4th week Basic optics and light-matter interaction (II): atomic polarizabalities, two-level atoms interacting with semi-classical field

    5th week Basic laser physics: rate equation model of the laser, gain saturation, lasering, transverse and longitudinal modes, stability zone

    6th week Ultrafast and nonlinear optics: ultrashort laser pulses, dispersion, 2nd and 3rd order nonlinearities

    7th week Ultrafast lasers: ultrashort pulse generation, ultrafast amplifier, ultrabroadband generation, attosecond

  • Things we will be talking aboutThings we will be talking aboutLight sources and tools, science/technology enabledLight sources and tools, science/technology enabled

    8th week: Static optical spectroscopy: FTIR, Raman/Rayleighscattering, multi-photon spectroscopy/microscopy

    9th week: Time-resolved optical spectroscopy basic concepts and instrumentations

    10th week: Coherent transient spectroscopy11th week: Ultrafast differential transmission/reflection spectroscopy:

    from visible, near-IR to mid-IR and THz12th week: Magneto-optics and ultrafast magneto-optical spectroscopy13th week: Selected topics: ultrafast photo-emission, transient grating

    spectroscopy, time-resolved photoluminescence, ultrafast electron diffraction, ultrafast X-ray spectroscopy

    14th week: Selected topics: optics of semiconductor nanostructures, quantum wells, wires and dots, single-wall carbonnanotubes, nano-particles, coherent control in femto-chemisitry, magnetic semiconductors, correlated electrons and more complex systemsFinal presentation and wrap up

  • ScoreScore

    Problem sets (occasionally) 10% Classroom discussion 10% Final presentation/reports 80%

    1. Conduct a through literature search on an assigned topic

    2. Describe what is new and why is interesting

    3. Describe who did what and identify the seminar paper

    4. Describe what is understood and what is not

    5. Describe what is controversial

    6. Try to propose a smoking gun experiment

    Problems, discussions & finalsProblems, discussions & finals

  • No required! No required! course materials will be drawn from reviewcourse materials will be drawn from review articles, articles, summer school lectures and recent book chapterssummer school lectures and recent book chapters

    Some Recommended General References:

    Lasers/Optical Spectroscopy:

    Demtroder, Laser Spectroscopy: Basic Concepts and Instrumentation

    A. Sigman, Lasers

    Max Born and Emil Wolf, Principles of optics

    Ultrafast Science and Technology, nonlinear optics

    Diels and Rudolph (DR), Ultrashort Laser Pulse Phenomena

    Rulliere, Femtosecond laser pulses

    Boyd, Nonlinear optics

    Applications of ultrafast spectroscopy to solid state physics/chemistry

    J. Shah, Ultrashort Spectroscopy of Semiconductors and Semiconductor Nanostructures

    Chemla, D.S., Ultrafast Transient Nonlinear Optical Processes in Semiconductors

    Mukamel, S, Principles of Nonlinear Optical Spectroscopy

    Text booksText books

  • TimescaleTimescales in Nature s in Nature

    Its routine to generate pulses < 1 picosecond (10-12 s).

    Researchers generate pulses a few femtoseconds (10-15 s) long.

    Such a pulse is to one minute as one minute is to the age of the universe.Such a pulse is to one second as 5 cents is to the US national debt.

    1 minute

    10 fs light pulse Age of universe

    Time (seconds)

    Computer clock cycle

    Camera flash

    Age of pyramids

    One month

    Human existence

    10-15 10-12 10-9 10-6 10-3 100 103 106 109 1012 1015 1018

    1 femtosecond 1 picosecond

    How fast is ultrafast? How fast is ultrafast?

  • Order of magnitudeOrder of magnitudein atoms, photons and solids in atoms, photons and solids

    Atom fields:H-atom ao = 0.53, Ry = 13.6 eV

    2ao Eat = Ry Eat 2.6*109 V/cm

    Light fields:I(W/cm2) E(V/cm) nph(cm-3)

    Mercury Lamp 1 10 108

    CW Laser 10 30 109

    Pulsed Laser 109 104 1017

    Focused pulsed Laser 1015 106 1023

  • Order of magnitudeOrder of magnitude


    1023 particles/cm3, quasi-particles and elementary excitationsVF 107 cm/s = 1 /fs Tlo = 2/lo = 115fsTpl = 2/pl = 150fs for neh = 5*1017cm-3

    Semiconductors Doping neh =1019 1020 cm-3, m=0.07 mo, =12, ao = 140,

    Ry = 4.2 meV

    Device Physicse.g., semiconductor Laser: P=1W, Wo 1m, I = 104W/cm2

    atoms, photons and solids atoms, photons and solids

  • Light is, in short, the most Light is, in short, the most refined form of matter.refined form of matter.

    Louis de Broglie

  • Optics Optics a brief historya brief history

    17th-century 18th-century 19th-century 20th-century



    Total internal reflection, Telescope, geometrical optics, the wave theory, prism dispersion, the particle theory of light

    Newton Fresnel, Young

    Interference, diffraction,expressions for reflected and transmitted waves,unified electricity and magnetism



    Light is (1) a phenomenon of empty space(2) both a wave and a particle

    Most fundamental questions, many prestigious names Most fundamental questions, many prestigious names

  • The story beginsThe story beginsAlbert Einstein, 1917Albert Einstein, 1917

    First proposed a theory to elucidate the physical process behind laser

    called stimulated emission

    but it will take your guys long time to prove it!

    First demonstration: Maiman, 1960

  • The Amazing LightThe Amazing Light LaserLaser

    A laser will lase if the beam increases in irradiance during a round trip:that is, if I3 > I0.

    Light amplification of stimulated emission of radiation

  • The worldThe worlds largest lasers largest laserAlmost 10 years journey, just dedicated!

    192 shaped pulses; 1.8 MJ total energy

    National Ignition Facility(LLNL)


  • ~ 250 10-18 s13 nm

    What is the shortest event ever created?What is the shortest event ever created?A single attosecond pulse