Polariton Physics and Devices Pavlos G Savvidis Dept

Polariton Physics and Devices Pavlos G. Savvidis Dept of Materials Sci. & Tech Microelectronics Group University of Crete / IESL

Engineering Light Matter Interactions • modify photonic and electronic wavefunctions in semiconductor heterostructures d~l Al. As T QD eδ high finesse cavity l Ga. As Confined electronic states: band gap energy modulation photons: refractive index modulation • enhance, inhibit spontaneous radiation • new properties, novel interactions, novel emitters FORTH Microelectronics Research Group Univ. of Crete

Weak Coupling Regime γ: loss channel (e. g. imperfect Ω γ Weak Coupling Regime (γ>>Ω) : mirror) Ω coupling strength between optical transition of the material and the resonance photon mode emitted photon leaves the resonator (after some reflections) no reabsorption Þ Spontaneous Emission is irreversible FORTH Microelectronics Research Group Univ. of Crete

Strong Coupling Regime γ: loss channel γ Ω Strong Coupling Regime (Ω>>γ) : Ω coupling strength between optical transition of the material and the resonance photon mode emitted photon will be reabsorbed before it leaves the cavity Þ Spontaneous Emission is a reversible process Polaritons FORTH Microelectronics Research Group Univ. of Crete

Research Activities Ga. As Polariton LEDs & Lasers • Ultralow threshold lasers Bragg Polaritons Strong Coupling in Ga. N Microcavties • Robust polariton devices at RT Hybrid Organic-Inorganic LEDs • Very strong nonlinearities - common idea of engineering light matter interactions at nanoscale

Polariton Light Emitting Diode (LED) Polariton electroluminescence up to room temperature EL intensity C Temperature (K) X X C Energy (e. V) S. I. Tsintzos, N. T. Pelekanos, G. Konstantinidis, Z. Hatzopoulos, P. G. Savvidis, Nature 453, 372 (2008)

Strong exciton-Bragg mode coupling regime Bragg polaritons 30 K A. Askitopoulos et al. , Phys. Rev. Lett. 106, 076401 (2011)

People Group Prof. PG Savvidis Dr. Peter Eldridge Dr. Simos Tsintzos Dr. Manolis Trichas Ph. D Niccolo Somaschi Ph. D Panos Tsotsis Ph. D Tingge Gao Ph. D Kostas Daskalakis Alumni MS A. Askitopoulos MS C. Xenogianni MS N. Xatzidimitriou MS P. Tsotsis University of Cambridge Prof. J. J. Baumberg Dr. G. Christmann Collaborators Prof. Pelekanos Materials Prof. Z. Hatzopoulos Physics Prof. Iliopoulos Physics Prof. I Perakis Physics University of Sheffield Prof D. Lidzey University of Southampton Prof P. Lagoudakis Dr. G. Kostantinidis IESL Dr. G. Deligeorgis IESL University of Durham Prof. M. Kaliteevski

Funding Selected Publications Principle Investigator in: EU FP 7 : ITN grants A. Askitopoulos, Phys. Rev. Lett. 106, 076401 (2011) 2009 -2013 “CLERMONT 4” Polariton Lasers G. Christmann, Appl. Phys. Lett. 98, 081111 (2011) 2009 -2013 “ICARUS” Hybrid Materials G Dialynas, J. Appl. Phys. 108, 103525 (2010) G. Christmann, Phys. Rev. B 82, 113308 (2010) National: E. Trichas, Appl. Phys. Lett. 94, 173505 (2009) 2005 -2010 PENED’ 03 Ga. N Microcavities S. I. Tsintzos, Appl. Phys. Lett. 94, 071109 (2009) 2006 -2010 Pythagoras II Organic Microcavities G. E. Dialynas, Int. Jour. l of Nanotechnology 6, 124 (2009) 2010 -2013 Herakleitos II Polariton Devices S. I. Tsintzos, Nature 453, 372 (2008) Industrial Mesophotonics Ltd. (PENED’ 03) Total Funding 2005 -2010 : ~ 1 M Euro

Ultrafast Lab

New Physics & Applications • Strong-coupling provides a new insight into a number of very interesting fundamental physical processes Polaritons are Bosons - Bose condensation - stimulated scattering Polariton vs Photon Laser Deng, et al. Natl. Acad. Sci. 15318 (2003) - ultralow threshold polariton lasers - all optical switches and amplifiers FORTH Microelectronics Research Group Univ. of Crete