Diamond is the host for more than 500 optically active defects. Some of them represent significant interest not only in jewelry but also in quantum technologies. For instance, nitrogen-vacancy center was extensively studied over the last two decades because of its potential applications in sensing and quantum information processing. However, the poor optical properties of this defect limit construction of the scalable quantum registers or quantum networks. Recently emerged new family of diamond defects based on group-IV elements demonstrate superior optical characteristics and keep a promise to become a new platform for the realization of quantum networks. In this talk, I will discuss optical and spin properties of the group-IV defects, show recent progress in fabrication, studies, and application. I will also outline our approach combining long-lasting memory with the nearly ideal optical interface.

We report an efficient way to generate both even and odd optical analogs of Schrӧdinger cat states (SCSs) which are a superposition of two coherent states with opposite amplitudes. The resources consumed are single mode squeezed vacuum (SMSV) state and single photons. SCSs are formed after superimposing the input states with the subsequent detection of the number of photons in the auxiliary mode. We report the generation of eve/odd SCSs of amplitude 4.2 with fidelity >0.99 and an acceptable for offline experiments success probability. There is a tendency towards an increase in the size of the SCSs more demonstrated with an increase in the number of extracted photons. Entanglement is a key resource for quantum information processing, and so algorithms to generate entangled states on various hardware platforms are in demand. Extending the method allows us to generate multipartite entangled states (GHZ, W, cluster states) with SCSs.

Краткое введение в цифровую связь, включая радио- и оптоволоконные системы. Как биты информации кодируются физическими сигналами. Что такое когерентная связь и в чем ее преимущества. Коррекция ошибок. Как это все реализовано, например, в Wi-Fi и в магистральных оптических сетях.

Ever since Antoni van Leeuwenhoek built his single-lens microscope in the late 1600s, optical microscopy has remained instrumental in many scientific disciplines. However, conventional optical imaging still suffers from many limitations. The confluence of advanced computational methods and the exponential growth of computing power helps to revolutionize far-field optical imaging by rethinking both the optical design and the post-processing. I will show how computational methods push the boundaries of optical microscopy and provide imaging beyond the Abbe and Nyquist limits simultaneously in a simple and compact optical setup.

Quantum interference is a powerful instrument in modern quantum optics that can be used for precise time and phase measurements, generating entanglement and testifying non-locality of entangled systems. Nonlinear interferometry provides a new insight into quantum interference. A non-linear (SU(1,1)) interferometer can be obtained from a conventional linear interferometer by replacing the beam splitters with nonlinear media. Such interferometers indicate stability to the external losses and, at the same time, show an improvement in the phase sensitivity compared to their linear counterparts. Nonlinear interferometers are useful tools for creating single-mode sources and providing spectral engineering of light with different intensity profiles and mode contents. The interaction of matter with quantum light generated in the parametric down-conversion process and nonlinear interferometers leads to new phenomena which cannot be explained by semiclassical approaches. This talk will highlight our recent advances in quantum multimode nonlinear interferometers, their integrated implementations, generation of bright squeezed states of light with strong correlations within nonlinear interferometers, as well as in the interaction of matter with specific quantum states of light and new phenomena arising within such interaction.