FORTH/IESL

UNIVERSITY OF CRETE

Dept. of Materials Science and Technology

Nanoscale Optoelectronics Lab

FORTH
IESL

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Scientific directions


Electrically injected polariton lasers

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Contemporary electronics face ever-increasing obstacles in achieving higher speeds of operation. Down-scaling, which has served Moore’s law for decades, is approaching the inherent limits of semiconductor materials. Even though a number of novel approaches have managed to improve operating frequency and power consumption, it is commonly acknowledged that in the future, charged carriers will have to be replaced by information carriers that do not suffer from scattering, capacitance, and resistivity effects.    More...

Although photonic circuits have been proposed, a viable optical analog to an electronic transistor has yet to be identified, as switching and operating powers of these devices are typically high. Polaritons, which are hybrid states of light and electronic excitations, offer an attractive solution as they are a natural bridge between these two systems. Their excitonic component allows them to interact strongly, giving rise to the nonlinear functionality enjoyed by electrons. On the other hand, their photonic component restricts their dephasing, allowing them to carry information with minimal data loss. Notably, from the view of solid state physics, polaritons are bosonic particles with a particularly light effective mass. These properties allow for the condensation of polaritons into a massively occupied single low-energy state, which shows many similarities to atomic Bose-Einstein condensates. The macroscopic quantum properties of polariton condensates, combined with their photonic nature, make them ideal candidates for use in quantum information devices and all optical circuits. Several recent works address the possibility of optical manipulation of polariton condensate flow; however, these stop short of demonstrating actual gating of polariton condensate flow, a prerequisite for implementation of integrated optical circuits. In this work, a high-finesse microcavity sample fabricated into a ridge is utilized to develop an exciton-polariton condensate transistor switch. A polariton condensate formed by optical excitation serves as a source of polaritons, which are ballistically ejected along the channel as shown in Figure. Polariton propagation can be controlled using a second weaker beam that gates the polariton flux by modifying the energy landscape. In the absence of the gate beam the ballistically ejected polaritons can be used to efficiently feed collector polariton condensate forming at the edge of the ridge. Owing to the highly nonlinear nature of the collector condensate, attenuations approaching 90% can be achieved.

Participating members: Pavlos Savvidis, Simeon Tsintzos, Peter Eldridge, Pramod Kumar Sharma, Stefanos Chatziathanasiou, Giannis Paschos


Novel polariton devices

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The photonics research activity at the Department of Materials Science and Technology focusses on the study of fundamental properties as well as development of prototype devices utilizing bosonic light-matter quasiparticles called polaritons. The Polaritonics, research field, is a rapidly developing research area extremely rich in fundamental effects and increasingly promising for optoelectronic device applications. One key applications area which we address, is a new type of inversion-less lasers, namely polariton lasers, which rely on the formation of bosonic condensates of exciton polaritons. Such condensates do not require a population inversion and have very low operational threshold. Furthermore polariton condensates can potentially provide a near lossless transfer and manipulation of information that is encoded by light, with the mixed light-matter nature of polaritons creating a direct link between microelectronics and nonlinear optics.    More...

Participating members: Simeon Tsintzos, Panagiotis Tsotsis, Peter Eldridge, Alexis Askitopoulos, Pramod Kumar Sharma, Stefanos Chatziathanasiou


On chip manipulation of polariton condensates

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Participating members: Simeon Tsintzos, Panagiotis Tsotsis, Tingge Gao, Peter Eldridge, Gabriel Christman, Iliana Harkoutsaki, John Balas


Nonlinear phenomena in strongly coupled GaN microcavities

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Participating members: Konstantinos Daskalakis, Pramod Kumar Sharma


Hybrid GaN microcavities

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Participating members: Manolis Trichas


Strong coupling and electrical injection in hybrid organic - inorganic microcavities

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Participating members: Niccolo Somaschi, Giannis Paschos


Polaritonic condensate circuits

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Participating members: Simeon Tsintzos, Alexandros Tzimis, Gabriel Christman, Iliana Harkoutsaki

 

 

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