Publications by Kosmas Tsakmakidis

Unconventional time-bandwidth performance of resonant cavities with nonreciprocal coupling

Camille Sophie Brès, Davide Grassani, Ivan Cardea, Kosmas Tsakmakidis

The time-bandwidth limit is a mathematical tenet that affects all reciprocal resonators, stating that the product of the spectral bandwidth that can couple into a resonant system and its characteristic energy decay time is always equal to 1. Here, we devel ...

2021

Arbitrarily high time bandwidth performance in a nonreciprocal optical resonator with broken time invariance

Camille Sophie Brès, Hatice Altug, Davide Grassani, Simon Julien Fabbri, Ivan Cardea, Kosmas Tsakmakidis

Most present-day resonant systems, throughout physics and engineering, are characterized by a strict time-reversal symmetry between the rates of energy coupled in and out of the system, which leads to a trade-off between how long a wave can be stored in th ...

Nature Research2020

Ultrabroadband 3D invisibility with fast-light cloaks

Hatice Altug, Dordaneh Etezadi, Kosmas Tsakmakidis, Ershad Mohammadi, Foziyeh Sohrabi

An invisibility cloak should completely hide an object from an observer, ideally across the visible spectrum and for all angles of incidence and polarizations of light, in three dimensions. However, until now, all such devices have been limited to either s ...

Nature Research2019

Gain enhancement of circular waveguide antennas using near-zero index metamaterials

Kosmas Tsakmakidis, Ershad Mohammadi, Foziyeh Sohrabi

In this article, a rigorous analytical methodology is introduced for designing near-zero refractive index metamaterials (NZIMs). Our proposed NZIM media is realized by three stacked layers of perforated metallic surfaces, each layer composed of a fishnet-l ...

WILEY2019

Accessible Superchiral Near-Fields Driven by Tailored Electric and Magnetic Resonances in All-Dielectric Nanostructures

Hatice Altug, Andreas Tittl, Yasaman Jahani, Kosmas Tsakmakidis, Ershad Mohammadi

Detection and differentiation of enantiomers in small quantities are crucially important in many scientific fields, including biology, chemistry, and pharmacy. Chiral molecules manifest their handedness in their interaction with the chiral state of light ( ...

AMER CHEMICAL SOC2019

Nanophotonic Platforms for Enhanced Chiral Sensing

Hatice Altug, Kosmas Tsakmakidis, Ershad Mohammadi

Chirality plays an essential role in life, providing unique functionalities to a wide range of biomolecules, chemicals, and drugs, which makes chiral sensing and analysis critically important. The wider application of chiral sensing continues to be constra ...

2018

Tunable polarization-sensitive optical nanoswitches based on spheroidal core-shell nanoparticles

Kosmas Tsakmakidis, Ershad Mohammadi, Foziyeh Sohrabi

2018

Overcoming the time-bandwidth limit

Camille Sophie Brès, Davide Grassani, Simon Julien Fabbri, Ivan Cardea, Kosmas Tsakmakidis

We are so accustomed to the time-bandwidth limit that we often take it to be a fundamental relation that cannot be overcome. Contrary to this belief we here propose that the storage/delay time of a system can in fact be decoupled from the operating bandwid ...

IEEE2018

Breaking Lorentz reciprocity to overcome the time-bandwidth limit in physics and engineering

Hatice Altug, Kosmas Tsakmakidis

A century-old tenet in physics and engineering asserts that any type of system, having bandwidth Delta omega, can interact with a wave over only a constrained time period Delta t inversely proportional to the bandwidth (Delta t-Delta w similar to 2 pi). Th ...

American Association for the Advancement of Science2017