Mediaspace scheduled maintenance: Aug 25, 2026 07:00 - 12:00 AM. During this time, videos will be temporarily unavailable. Check status updates.

Lecture

Light Propagation and Absorption

In course

PHYS-317: Optics I

L'optique est un vieux domaine qui touche à beaucoup de sujets modernes, des techniques expérimentales aux applications courantes. Ce premier cours traite plusieurs aspects de base de l'optique: propagation, dispersion, interférence, diffraction, polarisat ...

Description

This lecture covers the propagation of light in different media, including dispersion, refraction, reflection, and absorption. It explains the behavior of light in conductors, semiconductors, and metals, focusing on the wave equations and attenuation. The lecture also discusses the reasons behind the color of the sky, clouds, and sunsets, based on Rayleigh and Mie scattering. Additionally, it delves into the interaction between electromagnetic waves and matter, particularly in dielectric materials. The concepts of polarization, resonance, and dispersion in materials are explored, along with the Fresnel equations for reflection and transmission at interfaces.

Instructor

Benjamin Dwir

Academic title: Dr. Birth date: 24.10.1959 Nationality: Swiss At EPFL since: 1988

Official source

Ontological neighbourhood

Physics

Optics: Wave polarization

Related concepts (32)

Reflection (physics)

Reflection is the change in direction of a wavefront at an interface between two different media so that the wavefront returns into the medium from which it originated. Common examples include the reflection of light, sound and water waves. The law of reflection says that for specular reflection (for example at a mirror) the angle at which the wave is incident on the surface equals the angle at which it is reflected. In acoustics, reflection causes echoes and is used in sonar. In geology, it is important in the study of seismic waves.

Polarization (physics)

Polarization (also polarisation) is a property of transverse waves which specifies the geometrical orientation of the oscillations. In a transverse wave, the direction of the oscillation is perpendicular to the direction of motion of the wave. A simple example of a polarized transverse wave is vibrations traveling along a taut string (see image); for example, in a musical instrument like a guitar string. Depending on how the string is plucked, the vibrations can be in a vertical direction, horizontal direction, or at any angle perpendicular to the string.

Mie scattering

The Mie solution to Maxwell's equations (also known as the Lorenz–Mie solution, the Lorenz–Mie–Debye solution or Mie scattering) describes the scattering of an electromagnetic plane wave by a homogeneous sphere. The solution takes the form of an infinite series of spherical multipole partial waves. It is named after Gustav Mie. The term Mie solution is also used for solutions of Maxwell's equations for scattering by stratified spheres or by infinite cylinders, or other geometries where one can write separate equations for the radial and angular dependence of solutions.

Rayleigh scattering

Rayleigh scattering (ˈreɪli ), named after the 19th-century British physicist Lord Rayleigh (John William Strutt), is the predominantly elastic scattering of light or other electromagnetic radiation by particles much smaller than the wavelength of the radiation. For light frequencies well below the resonance frequency of the scattering particle (normal dispersion regime), the amount of scattering is inversely proportional to the fourth power of the wavelength. Rayleigh scattering results from the electric polarizability of the particles.

Specular reflection

Specular reflection, or regular reflection, is the mirror-like reflection of waves, such as light, from a surface. The law of reflection states that a reflected ray of light emerges from the reflecting surface at the same angle to the surface normal as the incident ray, but on the opposing side of the surface normal in the plane formed by the incident and reflected rays. This behavior was first described by Hero of Alexandria (AD c. 10–70). Later, Alhazen gave a complete statement of the law of reflection.

Related lectures (37)

Optical Propagation in Materials

Explores light propagation in various materials, absorption, dispersion, and scattering phenomena, including practical applications with laser beams.

Electromagnetic Waves and Optics

Covers the fundamentals of electromagnetic waves and optics, including interference phenomena, diffraction, refraction, and reflection of light.

Radiative Properties of Scattering: Rayleigh and Mie Theory

Discusses the radiative properties of particles, focusing on Rayleigh and Mie scattering theories and their applications in understanding light behavior.

Optical Interfaces: Reflection and Refraction

Explores reflection and refraction at optical interfaces, including Fresnel equations and practical applications.

Wigglers and Undulators: Tuning Photon Energy and Polarization