LIGHT-MATTER INTERACTION

The course is classified as one of the fundamental educational activities for the Bachelor Degree in Physical Engineering. It is aimed first of all at integrating the knowledge and the comprehension of the main physical phenomena related to the wave propagation within the matter, in particular necessary to frame correctly the interaction of the electromagnetic waves with the condensed matter. Then, this allows the student to integrate the knowledge of the physics of matter with the knowledge, both theoretical and applied, needed for studying the properties and the characterization techniques of specific materials, where the interaction or the propagation of radiation plays a major role. A further aspect considered throughout the course is the integrated sustainability of the materials which in turn the lessons refer to, thus framing the study within a general perspective of sustainability of the described applications.

The instructional goals of the course are:
1) development of the capability to apply to the study of materials the physical theories that describe the interaction of radiation with matter and its propagation;
2) development of a correct use of different and complementary approaches in the description of the physical and chemical properties depending on the wave propagation;
3) development of the capability to link concepts and theories to the experimental activity of characterization and study of the materials, also with reference to other courses with experimental character.

1. Knowledge and understanding
1.1. To know and understand the main theories which the propagation and the interaction of radiation with matter are based on, from both wave and particle points of view.
1.2. To know and understand the application fields of different approaches based on either semiclassical theories, for example the origin of the refractive index, or the quantum theory, for example the band structure.

2. Capability of applying knowledge and comprehension
2.1. To use the learned laws and concepts in the setting up of experiments for the characterization of materials.

3. Capability of judgement
3.1. To evaluate and choose critically the most suitable experimental approaches for the study of the properties of the different materials, pointing out the possible need for complementary techniques to guarantee the logical consistency and the reliability of the study.
3.2. To integrate the study based on the waves propagation with the information obtainable by different approaches, or related to different theoretical frameworks.
3.3. To frame the application potential of the studied materials within a general perspective of integrated sustainability.

4. Communication skills
4.1. To communicate both the knowledge and the effects of its application using the proper scientific language.
4.2. To interact with the teacher and with the other students in a constructive way, in particular during the experimental working groups activity.

5. Capability of learning
5.1. To take comprehensive and rigorous notes, even by the interaction with the other students.
5.2. To properly select the bibliographic references for the study, even by the interaction with the teacher, most of all for those contents that are not easily found in a single textbook.

Having achieved the learning outcomes of the fundamental courses of Mathematics and Physics of the first two years.

INTRODUCTION
Presentation and contextualization of the course within the academic curriculum.

REVIEW OF WAVE PHYSICS
Mechanical waves: D’Alembert’s equation, longitudinal and transverse waves, wavefronts, plane and spherical waves.
Harmonic waves: amplitude, phase, (angular) frequency, period, velocity, intensity, wave number and wave vector. Sound waves. Standing waves on a stretched string.
Electromagnetic waves: Maxwell’s equations in vacuum and in matter, wave equation, plane (harmonic) waves, wave packets, energy, polarization states.

PROPAGATION OF ELECTRIC AND MAGNETIC FIELDS
Radiation from an oscillating electric dipole: intensity, Larmor’s law. Atomic radiation: classical model, light scattering. Electromagnetic spectrum.

INTERFERENCE AND DIFFRACTION
Interference: wave superposition, rotating vector method, interference from two distant sources (Young’s experiment), interferometer: chromatic effects and wavelength measurements, N-source interference.
Diffraction: phenomenology; Huygens-Fresnel-Kirchhoff principle; Fraunhofer diffraction: slit, circular aperture, grating; resolution limit; polychromatic light; dispersive and resolving power.
Applications: grating spectroscopy; emission and absorption spectra; Fraunhofer lines; intrinsic and instrumental line broadening; holography; X-rays: generation, Bragg’s law, crystal planes and Miller indices, diffraction patterns, peak intensity, lattice parameters.

ELECTROMAGNETIC WAVES IN DIELECTRIC MATERIALS
Optical anisotropy: birefringence (ordinary and extraordinary waves), dichroic crystals, polarizers, analyzers, waveplates, field-induced birefringence (Kerr cell), stress-induced birefringence.
Interaction and propagation: harmonic field (complex notation), damped driven oscillator model, electric dipole and polarizability, dielectric polarization, wave equation in dielectrics.
Absorption and dispersion: Lambert-Beer law, complex refractive index, k-oscillator model, light dispersion and absorption in transparent media, anomalous refractive index behavior, group velocity.

ELECTROMAGNETIC WAVES IN CONDUCTIVE MATERIALS
Propagation and absorption: wave equations in conductors; low- and high-frequency approximations; plasma frequency.

QUANTUM TREATMENT OF RADIATION-MATTER INTERACTION
Blackbody radiation: definition, energy density and emissive power, stationary EM modes, Rayleigh-Jeans law, ultraviolet catastrophe, Planck’s law, Wien’s law, Stefan-Boltzmann law.
Photoelectric effect: experiments (Hertz, Hallwachs, Lenard, Millikan), Einstein’s hypothesis and equation, quantum explanation, photon number and light intensity, EM spectrum, absorption constraints.
Toward the laser: photon energy and momentum, Bohr model, photon emission/absorption, stimulated emission (Einstein 1917), laser operation: population inversion, metastable states, three-level pumping, features and types of lasers.
Matter waves and electron behavior in solids: de Broglie relation, wave-particle duality, Bohr’s complementarity and Heisenberg’s uncertainty principles; Drude-Sommerfeld model of free electron gas and introduction to band theory.
Scattering: emission, absorption, and scattering spectroscopy; light scattering: Rayleigh, Mie, and Raman scattering.

TECHNIQUES FOR MATERIAL CHARACTERIZATION
Synchrotron-based techniques: EXAFS spectroscopy, X-ray photoelectron spectroscopy (XPS), and resonant inelastic X-ray scattering (RIXS).

Any General Phisics textbook at a university level is in principle suitable for the part of wave mechanics. Possibly, the student will show the text to the teacher for approval. It is however suggested the text:
P. Mazzoldi, M. Nigro, C. Voci, “Fisica”, Vol. 2 (Elettromagnetismo e Onde), Edizioni EdiSES.
The part concerning the wave-matter interaction and the propagation within the matter is available in a wide bibliography, yet without a single textbook presenting all the course contents. The teacher will therefore address the source to use as reference for any single topic. Suggested general textbooks are:
N.W. Ashcroft, N.D. Mermin, “Solid State Physics”, Cengage Learning, Fort Worth 2003.
Specific material about topics that result difficult to find will be directly provided by the teacher.

The method used to assess the knowledge and skills acquired is one mandatory oral examination.
The oral exam consists first of all of a series of questions about all the programme presented in classroom and reported in the “Contents” Section: the student has to demonstrate both his/her acquisition of knowledge and the capability to present it in a formal rigorous way. Second, using the appropriate conceptual tools among those learned during the course, the student will be asked to develop a comprehensive response to a research question concerning the interpretation or the planning of some specific experimental activity. Finally, the student might also be asked to discuss and support the contents of his/her laboratory scientific report. The oral exam will last 30 to 45 minutes, and must be undergone within the official exam sessions. It has a lowest acceptable mark of 18/30 and a highest achievable mark of 30/30.

oral

A fully successful exam (27-30/30) will be deemed when a solid and broad mastery of the concepts discussed during the classes is demonstrated. An average grade (22-26/30) will be the result of fairly complete understanding of individual themes but with limited interconnection among subjects. A pass level (18-21/30) will correspond to a minimum knowledge of individual notions.

The course is entirely delivered through PowerPoint presentations. Most lectures are structured with a didactic and pedagogical focus, while some are presented in the form of more advanced scientific seminars. The blackboard is used only as a supporting tool when needed.
All course materials — including the slides and recorded lectures — are available on the University’s Moodle platform, along with specific lecture notes prepared by the instructor on selected advanced topics.

Accessibility, Disability and Inclusion
Accommodation and support services for students with disabilities and students with specific learning impairments:
Ca’ Foscari abides by Italian Law (Law 17/1999; Law 170/2010) regarding support services and accommodation available to students with disabilities. This includes students with mobility, visual, hearing and other disabilities (Law 17/1999), and specific learning impairments (Law 170/2010). In the case of disability or impairment that requires accommodations (i.e., alternate testing, readers, note takers or interpreters) please contact the Disability and Accessibility Offices in Student Services: disabilita@unive.it.
STRUCTURE AND CONTENT OF THE COURSE COULD CHANGE AS A RESULT OF THE COVID-19 EPIDEMIC.