Plasmonic nanoantenna design and fabrication based on evolutionary optimization

Abstract

Nanoantennas for light enhance light-matter interaction at the nanoscale making them useful in optical communication, sensing, and spectroscopy. So far nanoantenna engineering has been largely based on rules derived from the radio frequency domain which neglect the inertia of free metal electrons at optical frequencies causing phenomena such as complete field penetration, ohmic losses and plasmon resonances. Here we introduce a general and scalable evolutionary algorithm that accounts for topological constrains of the fabrication method and therefore yields unexpected nanoantenna designs exhibiting strong light localization and enhancement which can directly be "printed" by focused-ion beam milling. The fitness ranking in a hierarchy of such antennas is validated experimentally by two-photon photoluminescence. Analysis of the best antennas' operation principle shows that it deviates fundamentally from that of classical radio wave-inspired designs.Our work sets the stage for a widespread application of evolutionary optimization to a wide range of problems in nano photonics.

Numerical Optimization Methods for Metasurfaces

“…It has been shown recently that more than 100 bits can be used, as discussed in refs. [15,17] • Generating the random list of bits. During the initial generation of parent chromosomes, the bits in the chromosomes are randomly generated.…”

“…To properly deal with the extensive (often discrete) parameter space and the existence of several local optima, the majority of inverse design methods of interest for metasurface design are stochastic and include genetic algorithms and evolutionary strategies. [10][11][12][13][14][15][16][17][18] In addition to the methods discussed above, emergent approaches, including artificial neural networks and Bayesian optimization, have the potential to uncover surprising new metasurface designs. We will highlight in this review the key ideas behind these techniques and illustrate their versatility and advantages for the optimization of practical metasurfaces.…”

Optimizing the Nonlinear Optical Response of Plasmonic Metasurfaces

“…We then used the Genetic Algorithm (GA) optimization approach 40 to find the best one. GA is used extensively in optics, for example pulse shaping for coherent control [41][42][43][44][45] , and more recently for plasmonic design [46][47][48][49][50] in the linear regime.…”

Mueller polarimetry of discontinuous gold films

“…Thin films of gold are an important component of modern technology, and their role continues to grow. Widespread use of gold has taken place in plasmonics, where, due to its high optical conductivity and stability to the action of external factors, it is used as a material for creation of various bio-and chemical sensors [1,2], plasmon nanoantennas [3,4], medical and nutritional applications [5], etc. It is extremely important in this case to achieve the reproducible metal structure [6], the difficulties in this direction are one of the main factors inhibiting the propagation of biosensor devices.…”