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PH5193 - Laser Physics

Academic year

2021 to 2022 (Semester 1)

Key module information

SCOTCAT credits


The Scottish Credit Accumulation and Transfer (SCOTCAT) system allows credits gained in Scotland to be transferred between institutions. The number of credits associated with a module gives an indication of the amount of learning effort required by the learner. European Credit Transfer System (ECTS) credits are half the value of SCOTCAT credits.

SCQF level

SCQF level 11

The Scottish Credit and Qualifications Framework (SCQF) provides an indication of the complexity of award qualifications and associated learning and operates on an ascending numeric scale from Levels 1-12 with SCQF Level 10 equating to a Scottish undergraduate Honours degree.

Availability restrictions

This module is available only for those in the Engineering Doctorate in Applied Photonics and the MSc in Photonics and Optoelectronic Devices.

Module coordinator

Dr B D Sinclair

This information is given as indicative. Staff involved in a module may change at short notice depending on availability and circumstances.

Module description

This module presents a description of the main physical concepts upon which an understanding of laser materials, operations, and applications can be based. These concepts include a treatment of light-matter interaction, absorption and refractive index, rate-equation theory of lasers, gain and its saturation, frequency selection and tuning in lasers, transient phenomena, resonator and beam optics, and the principles and techniques of ultrashort pulse generation and measurement.

Assessment pattern

As used by St Andrews

2.5-hour Written Examination = 80%, Coursework = 20%

As defined by QAA

Written examinations = 80%
Practical examinations = 0%
Coursework = 20%

The Quality Assurance Agency (QAA) have compiled/developed an indicative list of learning and teaching methods:
  • Written: Is included in this category any assessment done under exam conditions (exams during diets, class tests) that do not involve the use of practical skills.
  • Practical: Are included in this category oral assessment and presentation as well as practical skills assessed in situ (in a classroom or laboratory for instance). Performances in the performing arts context are also classed as practical assessment.
Further details can be found on the QAA website.


Oral Re-assessment, capped at grade 7 = 100%

Learning and teaching methods and delivery

Weekly contact

2 or 3 x 1hr lectures x 10 weeks, 1hr tutorial x 4 weeks

Scheduled learning hours


The number of compulsory student:staff contact hours over the period of the module.

Guided independent study hours


The number of hours that students are expected to invest in independent study over the period of the module.

Additional information from school

PH5193 - Laser Physics


The course is designed to introduce the student to the classical treatment of laser physics providing the necessary quantitative techniques to permit design and prediction .A rate-equation model is used to model the laser system. In this course a number of variations are explored with regard to their applicability and limitations. Learning is assisted through the incorporation into the course of animations and numerical modelling material. (The latter is the 'Psst' software, which may be downloaded free for personal use.)

Aims & Objectives

The course aims to develop a working knowledge and conceptual understanding of important topics in contemporary laser physics at a quantitative level. A key objective is to enable the student to undertake quantitative problem-solving relating to the design, performance and applications of lasers through thereby acquiring an ability to put such knowledge into practice by way of numerical calculations. The aim throughout is to provide a thorough grounding in basic principles and their application, so that by the end of the course the student will have acquired a range of essential skills and knowledge required by a practitioner of laser physics and engineering. Such knowledge of the basics will be of enduring value and relevance. It will enable the student to innovate, design and analyse laser devices and systems at a quantitative level. As well as developing the conceptual framework the course also aims to give a sound perspective of contemporary trends and developments in laser physics, particularly with regard to new schemes for the generation of coherent electromagnetic radiation and the associated devices.

Learning Outcomes

You will have acquired:

  • A conceptual understanding of the classical approach to laser physics, and a perspective of areas of
  • An ability through a thorough grounding in the rate equation and strong signal approaches to analyse quantitatively the steady-state and dynamical performance of important contemporary laser devices.
  • A comprehensive knowledge, including of recent developments, concerning: solid-state lasers (including diode-laser pumped devices), semiconductor lasers, fibre lasers, vibronic and other tuneable lasers, organic lasers, laser amplifiers, and newly emerging gain media.
  • An ability to both analyse quantitatively and to design such lasers.
  • A conceptual understanding of such important aspects of laser active media as linewidth determining processes, dispersive/gain properties, spatial and frequency hole-burning.
  • An ability to both describe quantitatively and analyse such effects.
  • A thorough grounding in the principles and design of laser resonators, particularly stable cavities. - An ability to analyse quantitatively and design such cavities by using matrix techniques.
  • Access to and familiarity with numerical modelling tools (including 'Psst') relating to many aspects of laser design and performance.


  • Rate Equation Approach to Laser - Steady-State behaviour
  • Transient effects
  • Relaxation Oscillations
  • Q-switching
  • Diode-laser-pumped solid-state lasers
  • Optical Amplifier
  • Linear Gain Regime
  • Power Extraction
  • Dispersion & Gain in Laser
  • Mode Effects
  • Review of Stable Optical Resonators
  • Matrix Techniques
  • Applications
  • Fibre Lasers
  • Vibronic Lasers
  • Tuning Techniques
  • Linewidth Control
  • Frequency Stabilisation
  • Semiconductor Lasers
  • Ultrafast lasers and diagnostic techniques

Additional information on continuous assessment etc.

Please note that the definitive comments on continuous assessment will be communicated within the module. This section is intended to give an indication of the likely breakdown and timing of the continuous assessment.

The first part of the module looks at the key underlying ideas of laser physics. After an introductionwe look at laser gain. We then turn our attention to laser modes, both longitudinal and transverse. There follows a treatment of time dependence in lasers, based on coupled rate equations, and taking in relaxation oscillations and Q-switching. The remainder of the module looks at how all these ideas can be applied to understand and design various laser systems. We look at a number of case studies. The module then covers ultrashort pulse lasers and semiconductor diode lasers. Tutorials provide a way to practice using these ideas and to discuss questions. A group-based laser design case study with associated feedback allows a more in-depth exploration of design of a particular last system.

Laser Design Case Study 20%

Open Notes Examination 80%

Recommended Books

Please view University online record:

General Information

Please also read the general information in the School's honours handbook that is available via