Quantum Optics and Quantum Information

Members of the group:

Peter ADAM, associate professor, leader
Gabor MOGYOROSI, assistant research fellow
Ferenc BODOG, assistant research fellow

Former members:

Jozsef JANSZKY
, professor emeritus
Arpad VARGA
Emese MOLNAR

Research areas:

Periodic single-photon sources

There are many experiments and methods in the field of quantum optics and quantum information for which a traveling wave system generating single-photon states is of utmost importance. An ideal single-photon source can yield periodically highly indistinguishable single photons in an almost ideal single mode with known polarization. Widely investigated sources that can comply these criteria are heralded single-photon sources (HSPS) based on correlated photon pair generation in nonlinear optical media including spontaneous four-wave mixing (SFWM) in optical fibers and spontaneous parametric down-conversion (SPDC) in bulk crystals and waveguides. In the literature there are two suggested ways for overcoming the problem of the probabilistic nature of the pair generation and enhancing the single-photon probabilities without increasing the output noise: spatial multiplexing and time multiplexing.
Throughout our research we aim at further developing the theoretical description of the multiplexed periodic single-photon sources and elaborating methods that increase the single-photon probability in experimentally feasible schemes.

Selected papers:
F. Bodog, P. Adam, M. Mechler, I. Santa, and M. Koniorczyk: Optimization of periodic single-photon sources based on combined multiplexing, Phys. Rev. A 94, 033853 (2016).
P. Adam, M. Mechler, I. Santa, and M. Koniorczyk: Optimization of periodic single-photon sources, Phys. Rev. A 90, 053834 (2014).

Traveling wave generation of nonclassical states of light

Generation of nonclassical states of light is essential for the operation of various quantum optical systems and for the realization of certain methods in quantum information. Such states are necessary for optical quantum communication and they can be applied efficiently in quantum metrology. Especially important nonclassical states are, for example, photon number states, special superpositions of photon number states or coherent states, and amplitude-squeezed states.
Throughout our research we aim at developing experimentally feasible and practicable methods for generating nonclassical states of light in traveling wave optics. We devote special attention to the idea of quantum state engineering, that is, to the preparation of arbitrary quantum states in the same experimental scheme. In our research we utilize our previous results achieved in the field of coherent state representations, too.

Selected papers:
E. Molnar, P. Adam, G. Mogyorosi, and M. Mechler: Quantum state engineering via coherent-state superpositions in traveling optical fields, Phys. Rev. A 97, 023818 (2018).
P. Adam, E. Molnar, G. Mogyorosi, A. Varga, M. Mechler, and J. Janszky: Construction of quantum states by special superpositions of coherent states (invited paper), Phys. Scr. 90, 074021 (2015).
P. Adam, M. Mechler, V. Szalay, and M. Koniorczyk: Intelligent states for a number-operator–annihilation-operator uncertainty relation, Phys. Rev. A 89, 062108 (2014).