Esmaspäeval, 4 juunil 2018 kell 14.15 toimub Physicumis W.Ostwaldi 1 seminariruumis D312
Laserspektroskoopia ja tahkiseteooria seminar No 257
Esineb Ardi Loot , TÜ FI doktorant Füüsika, Tartu Ülikool
Enhanced spontaneous parametric down-conversion in plasmonic and dielectric structures (materials of PhD thesis)
An efficient generation of light in an entangled state has become increasingly important because of perspective applications in quantum optical experiments like quantum teleportation, quantum computing and quantum key distribution. The most common source of entangled photon pairs is a spontaneous parametric down-conversion (SPDC) process in a bulk nonlinear crystal – a spontaneous decay of pump photons into two due to nonlinear interaction with matter. However, the process of SPDC is very inefficient and only a small fraction of pump photons are transformed into photon pairs.
The topic of this seminar is to present the materials of PhD thesis where an idea to enhance the process of SPDC with surface waves is explored both theoretically and experimentally. To accurately model the enhancement process of SPDC in layered structures several extensions were developed for a standard transfer-matrix method. The new numerical method was used to address the suitability and to map the main limiting factors of three types of surface waves: surface plasmon polaritons, long-range surface plasmon polaritons and guided dielectric waves. It is found, that enhancement up to four orders of magnitude is possible, however only in miniature devices.