Ing Ind - Inf (Mag.)(ord. 270) - BV (478) NUCLEAR ENGINEERING - INGEGNERIA NUCLEARE
097589 - ADVANCED OPTICS AND LASERS
Ing Ind - Inf (Mag.)(ord. 270) - MI (476) ELECTRONICS ENGINEERING - INGEGNERIA ELETTRONICA
097589 - ADVANCED OPTICS AND LASERS
The course aims to provide students with a deeper insight of wave optics (interference, diffraction and propagation of light) and the basic concepts of laser physics and laser engineering. The principles of operation of the laser device, both in continuous wave operation and in specific pulsed regimes, are presented, and the main characteristics of laser radiation are discussed. Subsequently, a few significant types of laser are illustrated, in terms of principle of operation, main characteristics and performance, and applications to science and technology.
Some of the theoretical and practical classes will take advantage of the “blended learning” and “flipped classroom” innovative teaching methods in which the students will be directly involved in the learning process by carrying out laboratory experiments, writing reports or in collective brainstorming classes with the possibility of accessing to media content during the lesson.
Risultati di apprendimento attesi
Knowledge and understanding
At the end of the teaching, after passing the final test the student should be able to: • know and describe the physical and mathematical principles that governs wave propagation of light (interference, diffraction, generation and dispersion of optical pulses) • know and describe the working principles of optical devices that exploit the above phenomena for different purposes, including optical spectroscopy. • know and explain the physical and mathematical description that underlie laser operation as well as the physical and mathematical properties of laser light; • know the main characteristics of different types of lasers and different operating regimes • know the applications of lasers in industry, medicine, and basic science
Applying knowledge and understanding
The student should be able to apply the basic knowledge described above for: • Analyze and design basic interferometric devices and interferometry-based instrumentation and measurements • Model the laser behavior using proper mathematical tools as well as design elementary laser devices by suitably dimensioning the main components that constitute the laser • Model the space propagation of a laser beam and the temporal evolution of a laser pulse travelling through complex linear optical systems. • Design a complex laser system for a specific application by choosing, dimension and placing the required optical, electronic and laser components.
The oral moadality for the exam, as well as the need to fill-out written reports will improve the ability of the student of effectively communicating complex physical and engineering concepts and experimental results by making proper use of schemes, drawings, mathematical formulas and graphs. Also the limited time and space available will require skill in carefully choosing appropriate and effective key-words as well as synthetic concepts.
Wave optics: interference and diffraction of light (35 total hours of lectures, exercises and laboratories)
1. Wave properties of light and optical interferometry: • Wave-packets and dispersion, temporal and spatial coherence. • Michelson and Mach-Zehnder interferometers. Fourier Transform InfraRed (FTIR) spectrometers. • Interference in thin films. Multiple interference. • Fabry-Perot interferometer. Theory of multi-dielectric coatings.
2. Scalar theory of diffraction: • Rayleigh-Sommerfeld diffraction integral. Fresnel (near field) and Fraunhofer (far field) approximations. • Two-dimensional Fourier transformation by a positive thin lens. • Gaussian beams. Gaussian beam propagation through an optical system.
Principles of laser operation, technologies and applications (65 total hours of lectures, exercises and laboratories)
1. Fundamental principles of operation of the LASER: • Analogy between optical and electrical oscillators: Barkausen condition for oscillation. • Fundamental radiation-matter interactions, pumping systems. • Properties of laser beams. • Optical resonators: Q-factor, losses vs photon lifetime. Stability condition and eigenmodes. • Continuous wave (CW) operation of a laser: rate equations, threshold condition, output power.
2. Elements of quantum mechanics theory of laser: • Optical absorption, spontaneous and stimulated emission, non-radiative decay processes. • Optical transitions: transition cross section, mechanisms of transition line-broadening. • Energy levels and transitions in molecules and semiconductors.
3. Advanced principles of LASER operation: • Laser tuning. Multimode behaviour and single-mode selection techniques. • Dynamic behavior of lasers: relaxation oscillation of a laser. • Pulsed regime operation: Q-switching vs Mode-locking operation. • Ultrashort pulse generation and optical frequency stabilisation (Optical Frequency Combs).
4. LASER technologies: • Solid-state lasers: Neodimium lasers, Titanium:sapphire, Chromium lasers. • Fiber lasers: Erbium:fiber and Ytterbium:fiber lasers • Semiconductor lasers: homojunction and double heterojunction laser, quantum well lasers.
5. LASER applications: • Bio-Medical, industrial, communications, military, detection and ranging, spectroscopy applications. • Laser spectroscopy: ultrafast vs precision spectroscopy, laser stabilisation and frequency comb spectroscopy.
During the teaching three visits to the experimental laboratories will be carried out, in order to develop a link between theoretical lessons and experimental reality, Also this will give the students the possibility of interacting with the very sophisticated instrumentation present in a laser spectroscopy lab. In particular the topics of the visits will be the following:
1. Optical Interferometry (3 hours): the students will be able to exploit an optical interferometric setup (like the Michealson and Fabry-Perot interferometers) in order to perform precision measurements of physical quantities (like thickness, refractive index, wavelength…). A brief written report of the experiments carried out will be asked in the next few days following the laboratory experience. An extra score between 0 and 2 points that will be added to the final exam score will be awarded depending on the evaluation of this lab report.
2. Laser technologies and applications (3 hours): the students will have the opportunity to visit few research labs for advanced laser sources development, high-resolution spectroscopy, optical metrology and optical spectrometry located in the Physics Department. A detailed explanation of the experimental activity carried out in those labs will be given as well as answers to any questions. No report will be asked after this visit.
3. Laser stabilisation and precision spectroscopy (3 hours): the students will have the chance to approach a high-resolution spectroscopy laser system, understand the several electronics devices needed for frequency stabilisation and characterise several parameters of the system. Also for this lab experience a brief report will be asked and again from 0 to 2 extra points will be awarded to the final score.
The first laboratory will take place at the end of the first part of the teaching, regarding optical interferometry. The second and third laboratories will be scheduled close the end of the teaching.
Knowledge of the topics covered by the course of Electromagnetic Fields and Optics (Elettromagnetismo e Ottica) is an essential prerequisite of this teaching. A part from the above requirement, all the necessary notions and tools needed for a complete understanding of the arguments of the teaching will be given when needed along the teaching. A good ability in handling basic concepts of analog linear systems and signals as well as quantum mechanics concepts may however be helpful for a quicker and better understanding of some topics.
Modalità di valutazione
Assessment will be done through an oral exam which includes questions on the topics covered in the course and elementary exercises. The questions will always cover both macro arguments of the teaching (advanced optics + lasers principles). The oral test will grant a score up to 28 while 4 maximum additional points will be awarded by evaluation of lab reports. The student has six exam sessions available during the academic year in the periods set by the School. Some flexibility with respect to the official day and time of the exam will be accorded to students with specific needs and justifications.
Paolo Laporta, Interference and interferometers, Anno edizione: 2015 Note:
Paolo Laporta, Elements of diffraction theory, Anno edizione: 2015 Note:
Goodman, J.W., Introduction to Fourier Optics, Editore: Roberts and Company Publishers, Anno edizione: 2005
Pedrotti, F.L.; Pedrotti L.M.; Pedrotti L.S., Introduction to Optics, Editore: Addison-Wensley, Anno edizione: 2007, ISBN: 0131499335
Svelto Orazio, Principles of Lasers - V Ed., Editore: Springer, Anno edizione: 2010, ISBN: 0306457482
Cerullo, G.; Longhi, S.; Nisoli, M.; Svelto, O., Problems in Laser Physics, Editore: Kluwer-Plenum Press, Anno edizione: 2001
Tipo Forma Didattica
Ore di attività svolte in aula
Ore di studio autonome
Laboratorio Di Progetto
Informazioni in lingua inglese a supporto dell'internazionalizzazione
Insegnamento erogato in lingua
Disponibilità di materiale didattico/slides in lingua inglese
Disponibilità di libri di testo/bibliografia in lingua inglese
Possibilità di sostenere l'esame in lingua inglese
Disponibilità di supporto didattico in lingua inglese