Lasers

19 Outubro 2020, 14:00 • David de Castro Alves

Electrooptics

13 Outubro 2020, 09:00 • José Manuel Rebordão

Review: index ellipsoid (IE). Permittivity and permeability tensors.

EO effect. EO tensors (linear and quadratical). Effect of crystal class and group on the EO tensor. Deformation of the EO with the application of an electrical field. Examples.

Use of the EO effect to build light modulators. Half-wave tension. EO modulators of amplitude, polarization, phase and frequency (sidelobes).

BIBLIOGRAPHY

Saleh, Fundamentals of Photonics, Ch. 20.

NEXT CLASS

Electrooptics: Liquid crystals. Photorefractive materials. Non-linear optics.

Modulador Acústico-óptico

12 Outubro 2020, 15:00 • David de Castro Alves

Modulador Acústico-óptico

12 Outubro 2020, 14:00 • David de Castro Alves

Polarização

6 Outubro 2020, 09:00 • José Manuel Rebordão

EQUAÇÕES DE FRESNEL

Geometry, planes and natures of Fresnel coefficients. Role of Fresnel equations wrt the boundary conditions of Maxwell equations. Fresnel equations and interpretation of module and phase of the 4 coefficients. Reflectance and transmission.

POLARIZATION

The 3D E field as a synthesis of two orthogonal projections, with arbitrary relative amplitudes and phases. Limiting cases of linear, circular and elliptical polarization. Reference to the representation of polarization states: Poincaré sphere, Stokes parameters. Malus law.

Creation of polarization by reflection and dichroism.

BIRREFRINGENCE

The symmetries of the calcite and why dipoles should have different properties as a function of the polarization of the EM wave, in the context of the Lorentz model.

Electrical permittivity tensor as a symmetrical tensor if the Poynting vector retains its use to determine the direction and irradiance of the flow of energy of an EM wave. Symmetric tensors, quadratic forms, real eigenvalues and principal directions Impermeability tensor. Ellipsoid of the Indexes (EI).

How to use the EI to determine the polarization modes and their velocities in an anisotropic medium. Explanation of the value of the EI from Maxwell equations.

Uniaxial materials. Ordinary and extraordinary indexes. Particular cases: waves propagating along or perpendicularly to the optical axis.

Wave plates. Fast and slow axis. Half-wave plates and quarter-wave plates. Rotation of linear polarization and transformation between linear and circular polarization.

Example: How birefringence can be used in CD readers to ensure that the illumination and detection geometries are at 0 degrees.

A brief introduction to the electrooptic effect.

NEXT CLASS

Electrooptic effect and applications.

BIBLIOGRAPHY

Saleh, Fundamentals of Photonics, Ch. 6.