QuanTel

The main goals of the project are to investigate experimentally the possibility of generation of non-classical light states from epitaxial nanostructures at telecom wavelengths, in particular:

• Trains of indistinguishable photons
• Pairs of polarisation entangled photons from biexciton-exciton cascade.

These states are indispensable for implementation of quantum computation and quantum communication as well as cryptography schemes (e.g., quantum repeater) with the near infrared spectral range bringing them closer to practical limit. The nanostructures of interest are III-V semiconductor quantum dots (QDs) in two material systems:

• MOCVD-grown InGaAs/GaAs QDs exhibiting strain-induced redshift of the emission to the O-band suitable for short range quantum communication and local operations
• MBE-grown InAs/InP QDs operating at C-band providing minimal losses for long communication channels.

The results of the project will provide a new insight into the generation of indistinguishable photons and entangled photon pairs at telecom wavelengths using inherently quantum states provided by epitaxial QDs and will deepen our understanding of excitonic complexes in these structures. Demonstration and identification of determinants of the purity of respective non-classical states of light paves a way towards implementation of advanced quantum computation and communication schemes (e.g., quantum repeater, quantum cryptography) and makes a step in the direction of their practical use via integration into existing fiber networks which is of great importance in view of both studying fundamental phenomena in quantum optics as well as development of quantum technologies.