Lasers

Code:

FIS4027

Acronym:

FIS4027

Level:

500

Keywords
Classification	Keyword
OFICIAL	Physics

Instance: 2024/2025 - 2S

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

Cycles of Study/Courses

Acronym	No. of Students	Study Plan	Curricular Years	Credits UCN	Credits ECTS	Contact hours	Total Time
M:A_ASTR	1	Study plan since academic year 2024/2025	1	-	6	42	162
			2
M:EF	2	Official Study Plan since 2021_M:EF	1	-	6	42	162
M:F	3	Official Study Plan	1	-	6	42	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 - Quantum Electronics, Lasers, key topics, important applications, historical evolution

Interaction of radiation with atoms and ions - Blackbody radiation. Radiative processes, spontaneous emission, absorption and stimulated emission, the A and B Einstein coefficients. Lorentzian, Gaussian, and Voigt spectral profiles. Non-radiative decay. Degenerate and strongly coupled levels. Optical amplification.

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. 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 - . Pumping dynamics, relaxation oscillations. Operation in Q-switching, methods. Operation in mode-locking, methods, pulse propagation in saturable media, femtosecond regime, cavity dumping.

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.

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	100,00
Total:	100,00

Amount of time allocated to each course unit

designation	Time (hours)
Estudo autónomo	120,00
Frequência das aulas	42,00
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

Final written examination: 100%

Observations

Jury: