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B.S. LASER PHYSICS [PHYS-612] SYLLABUS
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Wave nature of light: Maxwell’s equations
for vacuum, phase and group velocities, polarized light, Maxwell’s
equations in a medium, applications of Maxwell’s equations to
dielectrics, materials-laser gain media, complex index of refraction,
optical constants, absorption and dispersion, coherence, temporal and
spatial, unique properties of lasers, laser spectrum and wavelength,
brief history of the lasers.
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Radiative transitions and emissions line width:
Decay of excited states, radiative and collisional decay in gases
and high density materials, natural line width, bordering due to collisional
decay, Doppler broadening and isotope shifts of gases, homogenous
and non-homogenous broadening, review of selections rules for electric
dipole, electric quadruple and other higher-order transitions.
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Energy levels and radiative properties of molecules, liquids
and solids: Review of molecular models, energy levels and
spectra, structure and energy levels of dye molecules, excitation
and emission of dye molecules, detrimental triplet states, energy
levels in solids, host materials, dope out lass, narrow-width laser
materials, ruby, neodymium, Alexandrite, titanium sapphire and Chromium
LiCaF lasers, broadening mechanism of solid-state lasers, energy levels
in solids-semiconductor laser material, excitation and decay of excited
energy levels, direct and indirect band gap semiconductors, recombination
radiation in p-n junctions, hetero-junction semiconductor materials,
quantum wells, variation of band gap and radiation allowed length
with alloy composition, line widths.
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Laser amplifiers: Absorption and gain on homogenously
and in-homogenously broadened radiative transitions, gain coefficients
and stimulated cross-section for homogenous and Doppler broadenings,
gain coefficient and stimulated emission cross-section and absorption
cross-section, population inversion and saturation intensity, development
and growth of a laser beam, exponential growth factor, threshold requirements
for a laser with and without mirrors, laser oscillation above threshold,
rate equations, small signal gain coefficient.
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Requirements for population inversion: Inversion
and two-level system, steady-state in three and four-level systems,
transient population inversions, radiation trapping in atoms and ions,
electron collisional excitation of the laser levels, absorption within
the gain medium.
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Laser pumping techniques: Optical and pout ride
pumping, direct and indirect pumping, specific pump-and-transfer processes,
requirements and geometries of optical pumping, transverse pumping,
electron-collisional pumping, heavy kautrits pumping.
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Laser resonator and modes: Fabry-Perot resonator,
longitudinal and transverse models, mode characteristics, spectral
and spatial-hole burnings, caused mirror counties, ABCD matrices,
stability criteria, properties of Gaussian and real laser beams, output-coupling
for a cavity, unstable resonator, Q-switching, methods for Q-switching,
model-locking theory and techniques for model-locking, mode-locking
theory and techniques for mode-locking, active and passive shutters,
pulse compression, reign and casers, counter for producing spectral
narrowing of laser output, tunable cavity.
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Specific laser systems: Description, laser structure,
excitation mechanisms and application of He-Ne, Argon-ion, Copper
vapor, CO2, excimer, nitrogen and free-electron, Dye, Ruby, Nd-Yg,
Alexandrite, Tiatnium sapphire, Chromium LiCaF, Fiber and semiconductor
diode laser. Note: This section can be used for student presentations
near the end of the semester.
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Recommended Text:
1. W. T. Silfvast, “Laser Fundamentals”, Cambridge
University Press (1996)
2. A. Yariv, “Optical electronics in Modern communications”,
5th Ed. Oxford Uni. Press (1997)
3. O. Svelto, “Principles of Lasers”, 2nd Ed. Plenum press
New York (1989).
4. Breck Hitz, J. J. Ewing and Jeff Hecht, “Introduction to
Laser Technology”, 3rd ed, IEEE Press (2001).
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