B.S. LASER PHYSICS [PHYS-612] SYLLABUS

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.

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.

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.

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.

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.

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.

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.

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.

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).