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

2. Engineering Light Matter Interactions FORTHMicroelectronics Research GroupUniv. of Crete • modify photonic and electronic wavefunctions • in semiconductor heterostructures d~l high finesse cavity AlAs AlAs T QD e- l δ GaAs Confined electronic states: band gap energy modulation photons: refractive index modulation • enhance, inhibit spontaneous radiation • new properties, novel interactions, novel emitters

3. FORTHMicroelectronics Research GroupUniv. of Crete Weak Coupling Regime γ: loss channel (e.g. imperfect mirror) γ Ω Ωcoupling strength between optical transition of the material and the resonance photon mode • Weak Coupling Regime (γ>>Ω): • emitted photon leaves the resonator • (after some reflections) no • reabsorption • Spontaneous Emission is irreversible

4. FORTHMicroelectronics Research GroupUniv. of Crete Strong Coupling Regime γ: loss channel γ Ω Ωcoupling strength between optical transition of the material and the resonance photon mode • Strong Coupling Regime (Ω>>γ): • emitted photon will be reabsorbed • before it leaves the cavity • Spontaneous Emission is a reversible process Polaritons

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

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

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

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

9. Funding Selected Publications Principle Investigator in: EU FP7 : ITN grants 2009-2013 “CLERMONT4” Polariton Lasers 2009-2013 “ICARUS” Hybrid Materials National: 2005-2010 PENED’03 GaN Microcavities 2006-2010 Pythagoras II Organic Microcavities 2010-2013 Herakleitos II Polariton Devices Industrial Mesophotonics Ltd. (PENED’03) Total Funding 2005-2010 : ~ 1M Euro • Askitopoulos, Phys. Rev. Lett. 106, 076401 (2011) • G. Christmann, Appl. Phys. Lett. 98, 081111 (2011) • G Dialynas, J. Appl. Phys. 108, 103525 (2010) • G. Christmann, Phys. Rev. B 82, 113308 (2010) • E. Trichas, Appl. Phys. Lett. 94, 173505 (2009) • S. I. Tsintzos, Appl. Phys. Lett. 94, 071109 (2009) • G. E. Dialynas, Int. Jour.l of Nanotechnology 6, 124 (2009) • S. I. Tsintzos, Nature 453, 372 (2008)

10. Ultrafast Lab

11. FORTHMicroelectronics Research GroupUniv. of Crete New Physics & Applications • Strong-coupling provides a new insight into anumber 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