OPTICS WITH LABORATORY
Basic elements of mathematics (derivatives, integrals, complex numbers) and electromagnetism.
The verification of learning stems on the following three elements:
1) The written report regarding the laboratory sessions. This report must contain, for each experiment (i) an introduction, clarifying the purpose of the work, (ii) a description of the experimental apparatus and how it was assembled, (iii) a description of the measurement process, (iv) a description of the results obtained, (v) a comment on the interpretation of the results. Originality, critical ability, synthesis, language accuracy, and the ability to follow the presentation scheme described above will be positively evaluated. The evaluation of the report will have a weight of 20% of the final evaluation.
2) The photographic documentation (smart phone quality) produced by the student regarding the occurrence of optical phenomena in nature. The originality of the subjects and the quality of the images will be positively evaluated. The evaluation will have a weight equal to 10% of the final evaluation.
3) The oral exam, focused on the topics covered in the lectures. A positive valuation will be given to: the critical ability, the capacity of establishing links between different topics, the property of language, the ability to describe the optical phenomena both from a theoretical point of view and making references to concrete examples, and the ability to clarify, with concrete examples, the limits of validity of the different approximations. The oral exam will comprise solving one or more exercise among those chosen by the student at the end of each session.
The outcome of the oral exam will account for 70% of the evaluation.
The educational objective of the course is to provide the student with the necessary knowledge to note, describe, understand, and manipulate the optical phenomena related to the propagation of light in the classical and linear regime, relying upon the approximate models of geometric optics and wave optics. Relevant examples are the processes of diffusion, reflection, refraction, polarization, diffraction, and interference of light. The theory presentation is enriched by laboratory activities, having the objective of teaching how to identify and characterize each phenomenon in the context of a complex phenomenology. Direct observation in nature will complete the course, to clarify to which extent the improved knowledge improves the sensorial perception of light and colours in the outdoor.
The student is expected to acquire the following skills:
1) a thorough understanding of the topics covered, and the ability to solve problems in these areas. In particular:
2) the ability to describe, qualitatively and quantitatively, the various optical phenomena covered by the course and how they occur in specific operating conditions;
3) the ability to describe the experimental apparatus and the measurement procedures needed to characterize the different phenomena.
4) the ability to identify relevant optical phenomena in the context of natural light.
The main teaching topics concern
The propagation of light:
Rayleigh scattering, propagation of light in dense media, refractive index, reflection, refraction, Huygens' principle, Fermat's principle, mirages, Fresnell's equations and the coefficients of reflection and transmission, total internal reflection.
Geometrical optics:
aspherical and spherical surface refraction, thin lenses, image formation, stops, aspherical, spherical and plane mirrors, prisms, optical fibers, optical systems, human eye, eyepieces, microscope, camera, binoculars, telescope.
More on Geometrical Optics:
thick lenses, ray tracing and matrix method, spherical aberration, coma, astigmatism, field curvature, distortion, chromatic aberration, achromatic optics.
The superposition of waves:
composition of waves of the same frequency, standing waves, composition of waves of different frequencies, beats, group velocity, the super and sub luminal waves, periodic waves and Fourier series, non-periodic waves and Fourier integrals, wave packet, the spectral band, coherence length.
Polarization:
linear, circular and elliptical polarization, polarizers, dichroism, birefringence, polarization by scattering, polarization by reflection, wave plates, circular polarizers, optical activity, optical modulators, Faraday, Kerr, and Pockels effects, liquid crystals and displays.
Interference:
Interference and spatial and temporal coherence, tilted waves and spatiotemporal coherence, fringes visibility, mutual coherence and degrees of coherence, wavefront splitting and amplitude splitting interferometers, multiple interference and Febry-Perot interferometer, multilayered films and anti-reflective coatings.
Diffraction:
Huygens-Fresnel principle, Fraunhofer diffraction, single, double and multiple slits, rectangular and circular apertures, diffraction grating, Fresnel diffraction, circular aperture and “vibration curve”, Fresnell lenses, rectangular aperture and Cornu spiral, Fresnels diffraction by a slit and a thin stopper, Babinet principle.
Fourier's optics:
Fourier transforms of representative functions, applications to optical fields, the convolution integral, Fourier analysis and Fraunhofer diffraction, power spectrum and auto and cross correlation functions.
Atmospheric optical phenomena: reflections on the water, images of the sun, rainbow, fog-bow, glory, broken specter, halo, corona, pillars, Heiligenshein, iridescent clouds, noctilucent clouds, sun dogs, dark rays, blue cave, rings and the rays around the sun.
Reconstruction of atmospheric optical phenomena according to CoeLux technology:
reconstruction of sky light by nano-structured optical diffusers, reconstruction of cloud light by microstructural diffusers, nano PDLC (polymeric dispersed liquid crystals) for the dynamic reconstruction of the light of the sun and the sky during the course of the day, the infinite depth of view reconstruction of sun light.
1. The Propagation of Light: Scattering, Reflection, Refraction, Total Internal Reflection, the Electromagnetic Approach and the Fresnel Equations.
2. Geometrical Optics: Lenses, Stops, Mirrors, Prisms, Thick Lenses, Lens Systems, Aberrations
3. The Superposition of Waves: Additions of waves of the same and different frequencies, Anharmonic Periodic Waves, Non Periodic Waves
4. Polarizations: Polarizers, Dichroism, Birefringence, Scattering and Polarizations, Polarization by reflection, Retarders, Circular Polarizers
5. Interference: Wavefront and Amplitude-splitting interferometers, Interference Fringes localization, Multiple beam interference
6. Diffraction: Fraunhofer Diffraction , Fresnel Diffraction
7. Fourier Optics: Fourier Transforms Optical Applications
8. Coherence: Visibility, Mutual Coherence, Degree of Coherence
The teaching method stems on three complementary actions: lectures, laboratory sessions and observation in nature.
(i) The lectures mostly follow the reference text, deepening and clarifying the most important and complex points, with special emphasis to the described phenomena. At the end of each section, the student is invited to choose and personally carry out some of the exercises presented in the reference text, and solved in the appendix.
(ii) The laboratory sessions are dedicated to set up the experimental apparatuses capable of highlighting the individual optical phenomena, and to carry out the qualitative and quantitative characterizations.
(iii) The observations in the outdoor are carried out by the students, being aimed at producing a photographic documentation of what they will be able to note during the semester.
The itinerary is completed by a visit to the laboratories of the academic spin-off CoeLux Srl, and by the presentation of technologies and products performing the physical reconstruction of atmospheric optical phenomena, for the indoor reproduction of natural light.