Accessibility statement

Atomic Physics & Lasers - PHY00065H

« Back to module search

  • Department: Physics
  • Module co-ordinator: Prof. Greg Tallents
  • Credit value: 10 credits
  • Credit level: H
  • Academic year of delivery: 2022-23

Module will run

Occurrence Teaching cycle
A Autumn Term 2022-23

Module aims

Students should develop a basic understanding of the quantum mechanical treatments of atomic and molecular structure and the phenomenological nature of the interaction of light with atoms. A basic awareness of the physics of lasers is subsequently developed.

Module learning outcomes

  • Construct energy level diagrams of the fine structure of hydrogen and hydrogen-like ions.
  • Describe the origin of sub-shells, terms and multiplets for atoms with two or more electrons not in closed sub-shells.
  • Describe molecular energy levels, including vibrational and rotational levels.
  • Derive the relationship between the Einstein coefficients.
  • Determine a general formula for laser gain in a generalised four-level laser.
  • Derive an expression for Doppler broadening of a line profile.
  • Describe mode locking of a laser cavity.
  • Describe the operation of helium-neon and carbon dioxide lasers.
  • Describe how lasers can be used to cool atoms to form, for example, Bose-Einstein condensates.

Module content


The quantum mechanics of atoms is introduced by re-visiting the hydrogen atom. Spin orbit splitting and the Lamb shift are introduced leading to a qualitative treatment of fine structure. Exchange parity and the Pauli exclusion principle are presented leading to a discussion of the structure of atoms with more than one electron. The inter-electron Coulomb and spin orbit interactions are introduced leading to a discussion of LS coupling and jj-coupling when there are two or more electrons not in closed sub-shells. The concept of sub-shells, terms and multiplets is presented. Molecular energy levels are introduced starting with the hydrogen molecule ion H2+ . Vibrational and rotational states are discussed. The interaction of light with atoms and molecules is further explored by re-visiting the Einstein A and B coefficient. This leads to a discussion on lasers and the gain coefficient. The concept of the lineshape function is introduced – Doppler broadening is considered. Laser cavities are briefly discussed leading to the concepts of longitudinal modes and mode locking. Helium-neon and carbon dioxide lasers are discussed. The technique of laser cooling is presented with a brief discussion of Bose-Einstein condensates.


Task Length % of module mark
Atomic Physics and Lasers Assignment 1
N/A 40
Atomic Physics and Lasers Assignment 2
N/A 60

Special assessment rules



Task Length % of module mark
Atomic Physics and Lasers Assignment 1
N/A 40
Atomic Physics and Lasers Assignment 2
N/A 60

Module feedback

Our policy on how you receive feedback for formative and summative purposes is contained in our Department Handbook.

Indicative reading

Haken H and Wolf H C: The Physics of Atoms and Quanta (Springer).

Hawkes J and Latimer I: Lasers: Theory and Practice (Prentice-Hall).

Tallents, G J ‘An introduction to the atomic and radiation physics of plasmas’ (Cambridge University Press)

The information on this page is indicative of the module that is currently on offer. The University is constantly exploring ways to enhance and improve its degree programmes and therefore reserves the right to make variations to the content and method of delivery of modules, and to discontinue modules, if such action is reasonably considered to be necessary by the University. Where appropriate, the University will notify and consult with affected students in advance about any changes that are required in line with the University's policy on the Approval of Modifications to Existing Taught Programmes of Study.