The laboratory deals with quantum key distribution through the line-of-sight optical channels. The advantage of this technology is its ability to share secret keys between moving targets or in the case of lacking optical fiber infrastructure. We explore both the theory and the experimental avenues for development.

The underlying theory that we study is more diverse than for the fiber-based solutions due to the presence of the spatial degree of freedom and turbulent perturbations in the channel. Properties of the free-space channel may be integrated into the QKD protocol itself in order to achieve superior results, as, for example, in our relativistic QKD protocol.

The experimental direction leads to the development of complete demonstration systems with active channel tracking and mobile hardware. Despite the readiness level lags behind the fiber-based solutions, free-space systems may become the key player in future quantum cryptography, as there is no better way to implement the last mile communication as well as to realize intercontinental satellite-based relay.