Optique physique | EPFL Graph Search

L'optique physique ou optique ondulatoire est la discipline qui étudie la lumière en la considérant comme étant une onde électromagnétique. L'optique ondulatoire s'attache plus particulièrement aux phénomènes affectant les ondes, comme les interférences et la diffraction. Principe La lumière pour aller d'un point à un autre se propage avec une vitesse déterminée. La lumière en un point donné sera l'addition cohérente ou incohérente du champ électromagnétique en ce point à l'instant t. Ce champ est ondulatoire ; cela signifie que la lumière est une onde se propageant avec une certaine vitesse. Ces propriétés entraînent de nombreux effets différents de l'optique géométrique. Par exemple, on assiste à des phénomènes d'interférence et de diffraction. Ces phénomènes ne se produisent que lorsque les sources sont cohérentes entre elles : la façon la plus simple d'y parvenir est d'utiliser une seule source, de la séparer en deux faisceaux, et de les ramener au même endroit.

Matrix Fourier optics enables a compact full-Stokes polarization camera

Recent developments have enabled the practical realization of optical elements in which the polarization of light may vary spatially. We present an extension of Fourier optics-matrix Fourier optics-for understanding these devices and apply it to the design and realization of metasurface gratings implementing arbitrary, parallel polarization analysis. We show how these gratings enable a compact, full-Stokes polarization camera without standard polarization optics. Our single-shot polarization camera requires no moving parts, specially patterned pixels, or conventional polarization optics and may enable the widespread adoption of polarization imaging in machine vision, remote sensing, and other areas.

2019

Crossed fiber optic Bessel beams for curvilinear optofluidic transport of dielectric particles

Fabrice Merenda, Kyunghwan Oh, René Salathé

Due to its unique non-diffracting and self-reconstructing nature, Bessel beams have been successfully adopted to trap multiple particles along the beam's axial direction. However, prior bulk-optic based Bessel beams have a fundamental form-factor limitation for in situ, in-vitro, and in-vivo applications. Here we present a novel implementation of Fourier optics along a single strand of hybrid optical fiber in a monolithic manner that can generate pseudo Bessel beam arrays in two-dimensional space. We successfully demonstrate unique optofluidic transport of the trapped dielectric particles along a curvilinear optical route by multiplexing the fiber optic pseudo Bessel beams. The proposed technique can form a new building block to realize reconfigurable optofluidic transportation of particulates that can break the limitations of both prior bulk-optic Bessel beam generation techniques and conventional microfluidic channels. (C) 2013 Optical Society of America

Optical Soc Amer2013

Advanced passive micro-optical elements

Micro-optical elements are optical elements having size or details in the range of the micrometer scale. The emergency of such elements is strongly linked to the development made in the fabrication techniques during the nineties to follow the still actual trend of miniaturization. From this time it has been convenient to separate micro-optical element having refractive or reflective optical design from those ones having strictly diffractive design. In the present thesis we are in between this two fields and from conventional refractive optical elements, different features of physical optics like diffraction, polarization or interference effects are added. We start by adding the birefringent property of liquid crystal polymers (LCP) to microlenses. The interest to employ LCP is linked to the fact that bulky birefringent structures of various shapes can easily be obtained by embossing. Moreover the choice of the optical axis of this material can be chosen by boundary conditions imposed by the different surfaces embedding the liquid crystal. Using this material a micro-optical device allowing the increase of the efficiency of conventional polarizer has been designed, simulated and realized. We continue by studying the influence of the aperture size on the position of the peak irradiance of microlenses. This diffractive effect of the aperture limitation is known as the focal shift which tends to decrease the real focal length obtained from paraxial geometric optics. In the frame of this thesis, we pursue the investigation and show that this effect could be advantageously used to obtain achromatic microlenses. In the frame of beam shaping applications we realized diffusers with very narrow angular distribution. These diffusers allow high energy throughputs and homogeneity distribution for highly coherent sources employed in conventional Fly's eye condensers. The consequences of coherent sources used in such beam shaper are discused in detail and rules are given to employ our diffusers in such systems. To finish, we developed and characterized a new method to fabricate concave microlenses with diffraction limited property and applied them in the realization of optical diffusers.

Institut de Microtechnique, Université de Neuchâtel2008

Advanced passive micro-optical elements

Institut de Microtechnique, Université de Neuchâtel2008