0000000000146837
AUTHOR
Lorenzo Sanchis
Properties of silicon integrated photonic lenses: bandwidth, chromatic aberration, and polarization dependence
We analyze the properties of silicon integrated photonic lenses based on scattering optical elements. The devices have been inverse- designed by combining genetic algorithms and the multiple scattering theory. These lenses are able to focus an infrared plane wave front on a position freely determined during the design stage. The nanofabricated silicon integrated lenses have proved effective over a large range of wave- lengths, measured to be of the order of 100 nm. The lenses show chromatic aberration, with a displacement of the position of the focus mea- sured to be higher than 1.5 μm when the wavelength varies from 1500 to 1600 nm. Moreover, we analyze the polarization of the focused beam…
Inverse design of photonic crystal devices
This work deals with the inverse design in the field of photonic crystal based devices. Here an inverse method containing a fast and accurate simulation method integrated with a competent optimization method is presented. Two designs yielded from this conjunction of multiple scattering theory with a genetic algorithm is analyzed. The potential of this approach is illustrated by designing a lens that has a very low F-number (F=0.47) and a conversion ratio of 11:1. We have also designed a coupler device that introduces the light from an optical fiber into a PC based wave-guide with a predicted coupling efficiency that exceeds 87%.
Three-dimensional axisymmetric cloak based on the cancellation of acoustic scattering from a sphere.
This Letter presents the design, fabrication, and experimental characterization of a directional threedimensional acoustic cloak for airborne sound. The cloak consists of 60 concentric acoustically rigid tori surrounding the cloaked object, a sphere of radius 4 cm. The major radii and positions of the tori along the symmetry axis are determined using the condition of complete cancellation of the acoustic field scattered from the sphere. They are obtained through an optimization technique that combines genetic algorithm and simulated annealing. The scattering cross section of the sphere with the cloak, which is the magnitude that is minimized, is calculated using the method of fundamental so…
Genetic Algorithms Applied to the Design of 3D Photonic Crystals
We aim at determining the optimal configuration of photonic crystal structures capable of carrying out a certain optical task. An exhaustive search would require a high computational cost, in this work we show how genetic algorithms can be applied to reliably find an optimal topology of threedimensional photonic crystals. The fitness, representing the performance of each potential configuration, is calculated by means of finite element analysis. Different experiments are presented in order to illustrate the potential of this 3D design approach.