Ardi Loot will defend his PhD thesis "Enhanced spontaneous parametric down-conversion in plasmonic and dielectric structures" on 22 August 2018.
Dr. Vladimir Hizhnyakov, Institute of Physics, University of Tartu, Estonia
Dr. Valter Kiisk, Institute of Physics, University of Tartu, Estonia
Dr. Ilmo Sildos, Institute of Physics, University of Tartu, Estonia
Dr. Sergey K. Sekatskii, Laboratory of the Physics of Living Matter, Ecole polytechnique fédérale de Lausanne, Switzerland
Quantum entanglement is considered to be one of the biggest “quirks” of quantum mechanics. One example is entangled pairs of photons – the measurement of one photon instantaneously influences the measurement outcome of the other photon despite the distance between them. Einstein considered it too strange to be true and called the phenomenon as “spooky action at a distance”. Today, this “quirk”, proved in several Bell test experiments, is considered to be the most important property of quantum mechanics and development of several applications based on it is in-progress: quantum cryptography, quantum computing, etc. The prerequisite for all of those future applications is an effective source of entangled particles. The most common source of pairs of entangled photons is spontaneous parametric down-conversion in nonlinear crystals. Essentially, the smallest quanta of light, photon, is split into two photons with a smaller energy due to a nonlinear interaction with matter. Unfortunately, this method is highly inefficient. The goal of this thesis is to enhance the efficiency of the entangled photon pair source by surface waves at the interface of a metal film. The enhancement of optical processes by surface waves is well established and experimentally verified. Despite it, the enhancement of spontaneous parametric down-conversion by surface waves is virtually unstudied to best of our knowledge. In this thesis, new computational methods were developed in order to study the enhancement of photon pair generation by surface waves. New methods were used to compare the effect of three different types of surface waves. In the experimental part of the thesis, a goniometric measurement setup was designed and built for investigating the enhancement of entangled pair generation and initial measurements were conducted. In conclusion, the computational methods developed in this work could be used in future to design, model and optimize a new type of objects. Moreover, the theoretical results and the description of the measurement setup is an important input to the future experimental work.