## Trinity College Dublin, The University of Dublin

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# PYU33P02 Electromagnetic Interactions I

Hilary Term – 30 Lectures – 5 credits (D O’Regan, W Blau)

Part I: Electromagnetic Theory
Part II: Quantum Optics & Lasers

Learning Outcomes
On successful completion of this module, students should be able to:

• Connect Maxwell’s Equations with the equivalent experimental laws
• Distinguish between polar and non-polar electric media and, by analogy, the different magnetic media
• Apply Maxwell’s Equations to the prediction of electromagnetic waves
• Explain when classical optics gives way to quantum optics
• Describe the operation of a laser in terms of population inversion and optical feedback
• Distinguish between spontaneous and stimulated emission, coherent and incoherent radiation, longitudinal mode and transverse modes
• Connect the laser properties of coherence and high brightness with applications in research, materials processing and communication

Syllabus

Part I: Electromagnetic Theory
Vector operators, Divergence and Stokes' theorems; Coulomb's and Gauss' Laws; dipoles and polarisation; electric susceptibility and displacement vector; polar dielectrics and Langevin analysis; potential and electric energy density; electrostatic boundary conditions and method of images; Biot-Savart and Ampere's Laws; magnetic dipole and magnetisation; H vector; vector potential; magnetic energy density; magnetostatic boundary conditions; dia, para and ferro magnetism; Faraday's law of electromagnetic induction; magnetoelectric induction; Maxwell's equations; plane waves; Poynting vector.

Part II: Quantum Optics & Lasers
Interaction of light with matter: black body radiation, the photoelectric effect, Einstein A and B coefficients. Light as photons. Coherence and fluctuations of real sources, correlation functions, photon statistics. Behaviour of photons in beam splitters, interferometers and cavities. The Raman effect. Basic laser theory: absorption and gain cross-section, saturation of absorption and gain, cavity lifetime and longitudinal modes, transverse mode structure, Gaussian beams. Three and four level lasers and power output in continuous wave lasers. Transient laser behaviour, relaxation oscillations, Q-switching, methods of Q-switching, mode-locking and methods of mode-locking. Specific laser systems: ruby and Nd-YAG/glass lasers, He-Ne laser, argon-ion laser, carbon-dioxide laser, excimer laser, dye laser and semiconductor diode laser.

 Assessment Weighting Examination – Exam in Quantum Optics & Lasers 50% Examination – Exam in Electromagnetic Theory 40% Continuous Assessment in Electromagnetic Theory 10%