In this paper we experimentally demonstrated a broadband scheme of the multiresonator quantum memory-interface. The microwave photonic scheme consists of the system of mini-resonators strongly interacting with a common broadband resonator coupled with the external waveguide. We have implemented the impedance matched quantum storage in this scheme via controllable tuning of the mini-resonator frequencies and coupling of the common resonator with the external waveguide. Proof-of-principal experiment has been demonstrated for broadband microwave pulses when the quantum efficiency of 16.3% was achieved at room temperature. By using the obtained experimental spectroscopic data, the dynamics of the signal retrieval has been simulated and promising results were found for high-Q mini-resonators in microwave and optical frequency ranges. The results pave the way for the experimental implementation of broadband quantum memory-interface with quite high efficiency η > 0.99 on the basis of modern technologies, including optical quantum memory at room temperature.

SrF2 and BaF2 crystals, doped with the Yb3+ ions, have been investigated by electron paramagnetic resonance and optical spectroscopy. As-grown crystals of SrF2 and BaF2 show the two paramagnetic centres for the cubic (Tc) and trigonal (T4) symmetries of the Yb3+ ions. Empirical diagrams of the energy levels were established and the potentials of the crystal field were determined. Information was obtained on the SrF2 and BaF2 phonon spectra from the electron-vibrational structure of the optical spectra. The crystal field parameters were used to analyse the crystal lattice distortions in the vicinity of the impurity ion and the F− ion compensating for the excess positive charge in T4. Within the frames of a superposition model, it is shown that three F− ions from the nearest surrounding cube, located symmetrically with respect to the C3 axis from the side of the ion-compensator, approach the impurity ion and cling to the axis of the centre when forming T4. The F− ion located on the axis of the centre between the Yb3+ ion and ion-compensator, also approaches close to the impurity ion.

The Yb 3+ paramagnetic center of the trigonal symmetry (''oxygen'' paramagnetic center T 2 ) in CaF 2 and SrF 2 single crystals is studied by EPR and optical spectroscopy. The Stark level energies of the Yb 3+ multiplets are established from absorption, luminescence and excitation luminescence spectra and the crystal field parameters are calculated. r

No abstract

No abstract