NFYA05020U Optical Physics and Lasers

Volume 2021/2022

BSc Programme in Physics


The course presents basic concepts of optical physics, including absorption and amplification of light by atoms, coherent light-atom interaction, physics of lasers, non-linear optics and elements of quantum optics. Both semiclassical and quantum mechanical theory of an atom in an optical field are covered.

Learning Outcome

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

  • Derive the Lorentzian lineshape function and explain the origin of the Doppler spectral width.
  • Derive expressions for the refractive index and 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 lasers.
  • 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 Gaussian beam propagation using ABCD matrix formalism.
  • understand the quantum theory of a two-level atom interacting with light including Rabi oscillations and Pi pulses.
  • understand the basics of coherent effects in laser-atom interactions, such as electromagnetically induced transparency.
  • explain the theory of nonlinear optical processes driven by laser light including second harmonic generation.


  • The basics of interaction of light with matter including absorption, stimulated and spontaneous emission of light
  • Lorentz model of atom-light interaction
  • The theory of spectral line shapes
  • Pulsed lasers
  • Optical resonators
  • Specific modern lasers
  • Atomic density matrix and Bloch equations
  • Quantum effects such as Rabi oscillations and electromagnetically induced transparency

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. The course should be also useful for students of other disciplines who expect to use lasers in one way or another.

See Absalon for final course material. The following is an example of expected course literature.

P.W. Milonni and J.H. Eberly, "Laser Physics" (Wiley)

First 2 years of the physics study
Lectures and exercise classes
  • Category
  • Hours
  • Lectures
  • 28
  • Preparation
  • 149,5
  • Theory exercises
  • 28
  • Exam
  • 0,5
  • Total
  • 206,0
7,5 ECTS
Type of assessment
Oral examination, 30 min
Students have up to 5 min preparation time during which they can use their notes.
All aids allowed
Marking scale
7-point grading scale
Censorship form
No external censorship
Several internal examiners

same as regular exam

Criteria for exam assesment

See 'Learning outcome'