Lecture

Diffraction Limit and Dispersive Media

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In course

EE-201: Electromagnetics II : field computation

Ce cours traite de l'électromagnétisme dans le vide et dans les milieux continus. A partir des principes fondamentaux de l'électromagnétisme, on établit les méthodes de résolution des équations de Maxwell dans le vide et dans des milieux matériels complexe ...

Description

This lecture discusses the diffraction limit of optical systems, explaining how objects smaller than a certain size cannot be resolved. It also covers the behavior of electromagnetic waves in dispersive media, such as how an optical microscope cannot distinguish between objects smaller than 400nm. The lecture delves into the concepts of evanescent waves and Lorentz materials, detailing how certain materials exhibit multiple resonances. Additionally, it explores the properties of dipole moments in materials and the plasma frequency in metals. The instructor emphasizes the limitations imposed by the diffraction limit and the characteristics of various materials when interacting with electromagnetic waves.

Instructor

Romain Christophe Rémy Fleury

Official source

Related concepts (32)

Lorentz force

In physics (specifically in electromagnetism), the Lorentz force (or electromagnetic force) is the combination of electric and magnetic force on a point charge due to electromagnetic fields. A particle of charge q moving with a velocity v in an electric field E and a magnetic field B experiences a force (in SI units) of It says that the electromagnetic force on a charge q is a combination of a force in the direction of the electric field E proportional to the magnitude of the field and the quantity of charge, and a force at right angles to the magnetic field B and the velocity v of the charge, proportional to the magnitude of the field, the charge, and the velocity.

Lorentz transformation

In physics, the Lorentz transformations are a six-parameter family of linear transformations from a coordinate frame in spacetime to another frame that moves at a constant velocity relative to the former. The respective inverse transformation is then parameterized by the negative of this velocity. The transformations are named after the Dutch physicist Hendrik Lorentz.

Lorentz ether theory

What is now often called Lorentz ether theory (LET) has its roots in Hendrik Lorentz's "theory of electrons", which marked the end of the development of the classical aether theories at the end of the 19th and at the beginning of the 20th century. Lorentz's initial theory was created between 1892 and 1895 and was based on removing assumptions about aether motion. It explained the failure of the negative aether drift experiments to first order in v/c by introducing an auxiliary variable called "local time" for connecting systems at rest and in motion in the aether.

Diffraction

Diffraction is the interference or bending of waves around the corners of an obstacle or through an aperture into the region of geometrical shadow of the obstacle/aperture. The diffracting object or aperture effectively becomes a secondary source of the propagating wave. Italian scientist Francesco Maria Grimaldi coined the word diffraction and was the first to record accurate observations of the phenomenon in 1660.

History of Lorentz transformations

The history of Lorentz transformations comprises the development of linear transformations forming the Lorentz group or Poincaré group preserving the Lorentz interval and the Minkowski inner product . In mathematics, transformations equivalent to what was later known as Lorentz transformations in various dimensions were discussed in the 19th century in relation to the theory of quadratic forms, hyperbolic geometry, Möbius geometry, and sphere geometry, which is connected to the fact that the group of motions in hyperbolic space, the Möbius group or projective special linear group, and the Laguerre group are isomorphic to the Lorentz group.

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