Lasers

Code:

F4018

Acronym:

F4018

Level:

400

Keywords
Classification	Keyword
OFICIAL	Physics

Instance: 2018/2019 - 2S

Active?	Yes
Responsible unit:	Department of Physics and Astronomy
Course/CS Responsible:	Master in Physics

Cycles of Study/Courses

Acronym	No. of Students	Study Plan	Curricular Years	Credits UCN	Credits ECTS	Contact hours	Total Time
M:F	2	Official Study Plan	1	-	6	49	162
MI:EF	10	study plan from 2017/18	4	-	6	49	162

Teaching language

Suitable for English-speaking students

Objectives

Training in basic laser physics, comprising the study of light-matter interaction from different approaches (classical, semi-classical and quantum), the study of gaussian beams and spherical optical cavities, laser amplification and oscillation in continuous-wave (cw) and in time-dependent (relaxation, Q-switching, mode-locking) regimes. Examples of specific laser systems and relevant recent applications in science and technology.
Laser physics and technology is a rapidly evolving field with a strong impact both in fundamental science and in applications. A solid training in the fundamentals of laser physics is therefore paramount for the succesful enrolment of students in new scientific and technological developments in the field.

Learning outcomes and competences

- Understanding of the fundamental physical processes and different operating regimes of a laser.
- Skills in analysis and calculation of specific laser systems and of the main characteristics of the emitted radiation in terms of power/energy, as well as in the spatial, spectral and temporal domains.
- Motivation for the study, optimization and development of laser technology and applications in several fields of Science and Technology (Physics, Medicine, Chemistry, Engineering, etc.) and in Industry.

Working method

Presencial

Pre-requirements (prior knowledge) and co-requirements (common knowledge)

The student should have previous (undergraduate level) training in optics, electromagnetism and basic quantum mechanics.

Program

Introduction and motivation
- A bit of history, evolution of laser technology, aplications, nonlinear optics, research and major laser projects worldwide, some of today's industrial panorama

Introductory concepts
- Spontaneous and stimulated emission and absorption
- The laser idea
- Overview of pumping schemes
- Basic properties of laser beams
- Types of lasers

Interaction of radiation with atoms and ions
- Summary of blackbody theory
- Spontaneous emission
- Absorption and stimulated emission
- Line broadening mechanisms
- Nonradiative decay and energy transfer
- Degenerate or strongly coupled levels
- Saturation
- Decay of an optically dense medium

Ray and wave propagation through optical media
- Matrix formulation of geometric optics
- Wave reflection and transmission at a dielectric interface
- Single and multilayer dielectric coatings
- The Fabry-Pérot interferometer
- Diffraction optics in the paraxial approximation
- Gaussian beams

Passive optical resonators
- Eigenmodes and eigenvalues
- Photon lifetime and cavity Q
- Stability condition
- Stable resonators
- Brief note on the use of unstable cavities

Pumping processes
- Optical, laser and electrical pumping (summary)

Continuous wave laser behavior
- Rate equations
- Threshold conditions and output power: four-level laser
- Optimum output coupling
- Laser tuning
- Reasons for multimode oscillation
- Single-mode selection
- Frequency-pulling and limit to monochromaticity

Transient laser behavior
(number of topics to be covered is dependent on the available time)
- Relaxation oscillations
- Q-switching
- Mode-locking

Mandatory literature

O. Svelto; Principles of Lasers, 5.th ed., Plenum Press, 2010
Cerullo G. 070; Problems in laser physics. ISBN: 978-0-306-46649-6 (Solutions to several problems in O. Svelto's book, or of variants of those problems)

Complementary Bibliography

P. W. Milonni, J. H. Eberly; Lasers, Wiley , J. Wiley, 1988
Karl F. Renk; Basic of Laser Physics for For Students of Science and Engineering, Springer, 2012. ISBN: 978-3-642-23564-1 (Very recent book. Focus on particularly relevant laser technologies today, such as femtosecond lasers (namely the Titanium:Sapphire laser) and semiconductor lasers)
A. E. Siegman; Lasers, University Science Books, 1986

Teaching methods and learning activities

Classes for presenting and discussing theoretical topics, with relevant examples, and for problem solving. Optional (but recommended) study visits to laser-based research laboratories at the Department of Physics and Astronomy and to companies developing lasers and laser technology in the Porto area.

Software

Psst! - Photonics Simulation Software for Teaching, disponível em https://www.st-andrews.ac.uk/~psst/

keywords

Technological sciences > Technology > Instrumentation technology > Laser technology
Physical sciences > Physics > Optics

Evaluation Type

Distributed evaluation with final exam

Assessment Components

designation	Weight (%)
Exame	85,00
Participação presencial	15,00
Total:	100,00

Amount of time allocated to each course unit

designation	Time (hours)
Estudo autónomo	113,00
Frequência das aulas	49,00
Total:	162,00

Eligibility for exams

In order to have access to the final examination, the student must attend a minimum of 75% of the antecipated teaching hours, in accordance with the Regulations of Assessment of Student Achievement of FCUP.

Calculation formula of final grade

Continuous assessment: 15%
Written examination: 85%

Continuous assessment will be based on participation in the theory and problem solving classes.

Classification improvement

Only the written examination component can be improved, in the second examination call ('recurso') .