Lesson Notes;
Dynamic Light scattering, B.Berne and R.Pecora;
Principles of laser, O.Svelto;
Learning Objectives
Learning of some optical techniques for the spectroscopic investigation of condensed phases.
Prerequisites
Laurea triennale
Teaching Methods
lessons and laboratory experience
Type of Assessment
Written report of the experimental experience and oral exame
Course program
Introduction (16 hours lesson):
Introduction to the physics of LASER sources and of basic interaction-radiation matter phenomena:
absorption, spontaneous and stimulated emission, equations for a two-level system, amplification phenomena, photon flow equations, equilibrium and out-of-equilibrium populations. Principle of operation of a laser source: constituent elements and feedback process, level pumping schemes. General definition of open cavities and modes of the field e.m .; longitudinal and transversal modes; simple calculation of resonant frequencies. Laser cavities: flat-parallel, concentric and confocal. Definition of the stability conditions of a laser cavity and stability of the different types of cavities. Introduction to the various active media present in lasers.
Radiation characteristics e.m. produced by Laser sources:
Spectral characteristics of multimode and single mode lasers, Definition of spatial and temporal coherence parameters and their measurement through interferometric measurements, directionality properties, limited beams by diffraction, definition and meaning of the Radiance / Intensity of a laser beam.
Introduction to optical spectroscopy experiments and description of an experimental set-up:
Light diffusion processes; single vs. multiple scattering, scattering processes from particles of different sizes (geometric, Mie and Rayleigh). Spontaneous scattering measures of light, resolved in the frequency domain (Raman-Brilluoin) and in the time domain (Optical Kerr Effect). Introduction to spectroscopy techniques based on non-linear optics and ultrashort pulsed sources.
Laboratory experiences (40 hours of laboratory):
I Experience: Measurements resolved in the frequency-domain, Raman spectroscopy.
II Experience: Measurements resolved in the time-domain, OKE spectroscopy.