Light is a form of electromagnetic waves, that can be controlled by material affecting their electric or magnetic properties. Manipulation of light has become quite sophisticated with the development of engineered materials, i.e., metamaterials. Metamaterials are composed of unit cells much smaller than the wavelength of an electromagnetic wave; this allows them to interact with waves.
In the present world things can change globally in few seconds. This, in turn, stems from humans' ability to mold and shape materials. The current well-connected world is possible because we can fabricate things at a nanometer scale.
The complex design of metamaterials requires sophisticated fabrication methods to obtain the desired electromagnetic properties. This becomes more challenging when the metamaterials are designed for the wavelength of light less than a micron.
“Professor Feynman said at APS annual meeting in 1959 that there is plenty of room at the bottom. That has kept me motivated to obtain such metamaterials that can control light,” Habib says.
Complex 3D metamaterials formed by simple thin films
In his research, Mohsin Habib designed and fabricated planar metal-dielectric metamaterials as epsilon-near-zero substrates. He focuses on the rolling of two thin films to form multilayer metamaterials. This rolling process brings a new dimension to 2D metamaterials and offers quite exciting applications.
“First, I designed and fabricated planar metamaterials that can control the resonances of plasmonic antenna due to the engineered optical properties. Then, I developed an extremely challenging method to obtain rolled-up tubes with thin films that can be used as 3D epsilon near zero metamaterials. These rolled-up tubes were further patterned to form 3D negative index materials and out-of-plane metasurfaces,” Habib explains.
“What intrigues me is that the thin films also have some stress and strain at nanometers. This strain can be actually controlled to form a rolled-up tube with desired sizes," he continues.
This dissertation brings a new perspective to the field of metamaterials by studying simple thin films and using them to form complex 3D metamaterials.
Since 2018, Mohsin Habib has been working on the development of multiple fabrication methods at the Metaplasmonics research group of Tampere University. The Ph.D. research was supported by the ERC Starting Grant funding in project aQUARiUM.
The doctoral dissertation of M.Sc. Mohsin Habib in the field of photonics titled Light Manipulation in Multilayer Metamaterials will be publicly examined in the Faculty of Engineering and Natural Sciences at Tampere University on Monday 20 June 2022 at 12:00 in the auditorium TB109 of the Tietotalo Building (Korkeakoulunkatu 3, Tampere). The Opponent will be PD Dr. Tobias Kipp from the Universität Hamburg, Germany. The Custos will be Associate Professor Humeyra Caglayan from the Metaplasmonics research group, Faculty of Engineering and Natural Sciences, Tampere University.
The dissertation is available online at the: https://urn.fi/URN:ISBN:978-952-03-2451-3
Photo: Rabia