NON LINEAR OPTICS
- Scheda dell'insegnamento
- Obiettivi formativi
- Metodi didattici
- Verifica dell'apprendimento
- Altre informazioni
- knowledge of the fundamental nonlinear optical phenomena (parametric and non-parametric ones) (Descriptor of Dublin: Knowledge and understanding)
- understanding the requirements and conditions to be met to achieve these processes (Descriptor of Dublin: Applying knowledge and understanding)
- ability to discriminate the different nonlinear processes, by understanding their origin and distinguishing between linear and nonlinear phenomena
(Descriptor of Dublin: Making judgements)
- knowledge of the main applications of nonlinear optics to science and technology (Descriptor of Dublin: Learning skills)
For a better understanding of the topics covered in the course, it is required that students have already attended courses of Electromagnetism and Physics of Matter. In addition, it is advisable that students have inserted the course of Optics in their learning program and that they have already attended it.
- Historical background and introduction to the main nonlinear optical phenomena (parametric and non-parametric ones) (4 hours);
- Passive mode-locking techniques obtained by means of nonlinear processes (Kerr lens mode-locking and saturable absorbers) (2 hours);
- Symmetry properties of the second-order nonlinear susceptibility tensor (2 hours);
- Linear optical systems and Kramers-Kronig relations in linear and nonlinear optics (2 hours);
- Second-order nonlinear processes under plane-wave approximation: second-harmonic generation, sum-frequency generation, parametric amplification and spontaneous parametric down conversion, optical parametric oscillator (7 hours);
- Phase-matching conditions and generation in phase-mismatch condition (3 hours);
- Generation of nonlinear processes by means of focused Gaussian beams (2 hours);
- Symmetry properties of third-order nonlinear susceptibility (1 hour);
- Description of the intensity-dependent refractive index of the non-linear medium (1 hour);
- Processes resulting from the intensity-dependent refractive index: self-phase modulation, self-focusing, filamentation, temporal solitons, phase conjugation (8 hours);
- Optically induced damage and multiphoton absorption (2 hours);
- Ultrafast and ultra-intense optics: nonlinear Schrödinger equation, white-light continuum and high-harmonic generation (4 hours).
The laboratory activities (roughly 10 hours) aim at directly observing and investigating some nonlinear optical phenomena, especially those related to second-order nonlinearity, already presented from the theoretical point of view.
In fact, on the basis of the available laser sources and instruments, the following processes can be studied:
- second-harmonic generation in collinear and non-collinear geometry: application to the measurement of short-pulse duration using the autocorrelation technique
- quantitative analysis of second-harmonic generation in phase-mismatch condition
- Sum- and difference-frequency generation: study of the processes as functions of the polarization of the input optical fields
- spontaneous parametric down conversion (SPDC): observation of SPDC cones and quantitative analysis of their spatial and spectral properties
- passive mode-locking technique: use of a laser source in which such a technique can be easily obtained and observed.
The course is essentially based on lectures (38 hours). In order to improve the quality of teaching and to make the content of theoretical lessons much more understandable, the remaining 10 hours will be devoted to the experimental observation and characterization of nonlinear optical processes in the laboratory.
The exam is oral and essentially divided into two parts. First of all, students are asked to choose and talk about a topic among those mentioned in the course. This part of the exam is aimed at verifying on the one hand the knowledge and understanding of a specific nonlinear process, and on the other hand the learning skills and the communication skills of the students.
In the second part of the exam, some questions about the remaining topics are asked, through which the professor will check if the students have not only acquired a sufficient knowledge of nonlinear optical phenomena (Descriptor of Dublin: Knowledge and understanding), but have also learnt skills in recognizing and understanding them (Descriptor of Dublin: Making judgements). Full mark with laude is assigned only to students that accomplish all the aims and outcomes discussed above. In particular, they must be able to re-elaborate the different topics, to establish connections and comparisons, and to make practical examples.
Lectures are based on the following textbooks: R. W. Boyd, “Nonlinear Optics”, Academic Press (2008); B. E. A. Saleh and M. C. Teich, “Fundamentals of Photonics”, John Wiley & Sons, Inc. (1991); V. G. Dmitriev, G. G. Gurzadyan, and D. N. Nikogosyan, “Handbook of Nonlinear Optical Crystals”, Springer (1999). Moreover, when it is the case, copies of some articles are provided during lessons. They can be also found on the e-learning platform.