André Stefanov - CINBIO Seminar Programme 09 abril 2024 Sala de seminarios da Torre CACTI

Programa Seminar Programme

O martes 9 de abril de 2024 o Dr. André Stefanov (Assistant Professor, Group Leader Quantum Optics Lab. University of Bern, Switzerland) ofrecerá o seminario "Spatial Entanglement with SPAD arrays", dentro do ciclo "CINBIO Seminar Programme".

Será ás 11:30h na Sala de seminarios de Torre CACTI.


We present the application of single photon avalanche diode (SPAD) arrays for the characterization of spatial entanglement of photon pairs produced by spontaneous parametric downconversion (SPDC). We make use of recently developed CMOS SPAD arrays with up to 224x272 pixels and 200 ps temporal resolution.

Thanks to their high temporal resolution and high repetition rate, those sensors allow us to measure the full correlation map between each pixel pairs within a short time window and the acquisition time is competitive with commercial single photon sensitive CCD cameras. We further quantify the strength of the correlations in the near-field of the SPDC emission and of the anti-correlations in the far-field. The product of those quantities violates a classical inequality, proving the quantum nature of the correlations.

We then characterize the spatial entanglement of photon pairs after their interaction with nanopillar arrays. We don't observe any significant change in spatial entanglement, thus concluding that spatial entanglement is preserved in the interaction.

Finally, we exploit entanglement to implement a quantum imaging scheme, where the effective resolution of the optical system is improved by a factor two compared to a classical imaging system.


André Stefanov received the M.S. and Ph.D. degrees in physics from the University of Geneva, Geneva, Switzerland, in 1999 and 2003, respectively. From 2003 to 2008, he was with the University of Vienna, Vienna, Austria, and the University of Bristol, Bristol, U.K., working on quantum interferences with large molecules and multiphoton quantum states for quantum information. From 2008 to 2011, he was the Head of the Time and Frequency Laboratory, Federal Institute of Metrology Laboratory Photonics, Bern-Wabern, Switzerland. Since 2012, he has been the Group Leader of the Quantum Metrology Laboratory, Institute of Applied Physics, University of Bern, Switzerland. His current research interests include the application of quantum states of light to new measurement methods as quantum imaging and quantum spectroscopy and the application of single photon imaging to investigate the propagation of light in scattering media.