Optical Physics and Lasers

Skills
Upon completion of the course the student should be able to:

• Explain spectrum of light-atom interaction including spontaneous emission, collisions and atomic motion.
• Derive expressions for the refractive index, absorption and gain coefficients of atomic medium.
• Understand the origin of laser gain, losses and the feedback mechanism and the laser threshold.
• Explain photon- and population rate equations for three- and four-level atoms.
• Explain the difference between saturated gain and small signal gain of a laser.
• Discuss the nature of the laser linewidth and methods of obtaining single mode operation.
• Explain the origin of the theoretical lower limit for laser bandwidth (Schawlow-Townes limit). understand the principles of Q-switch lasers and mode-locked lasers.
• Calculate optical wave propagation for Gaussian beams using ABCD matrix formalism.
• Understand the quantum theory of a two-level atom – an atomic qubit - interacting with light, including Rabi oscillations and Pi pulses.
• Understand the basics of coherent effects in light-atom interactions for three level atoms, such as electromagnetically induced transparency.
• Explain the theory of nonlinear optical processes driven by laser light including second harmonic generation.

Knowledge

• The basics of interaction of light with matter including absorption, stimulated and spontaneous emission of photons
• Lorentz model of atom-light interaction
• The theory of atomic spectral line shapes
• Pulsed lasers
• Optical resonators
• Specific modern lasers
• Atomic density matrix and Bloch equations
• Basics of operations on atomic two-level system – qubits, such as Rabi oscillations
• Basics of coherent evolution of three-level atoms including electromagnetically induced transparency

Competences
The course forms the basis for future studies of coherent and quantum effects within atomic and optical domains including quantum optics, quantum solid state photonics and experimental realizations of quantum information processing and quantum technologies. The course should be also useful for students of other disciplines who expect to use lasers in one way or another.