Entanglement between a diamond spin qubit and a photonic time-bin qubit at telecom wavelength

We report on the realization and verification of quantum entanglement between an NV electron spin qubit and a telecom-band photonic qubit. First we generate entanglement between the spin qubit and a 637 nm photonic time-bin qubit, followed by photonic quantum frequency conversion that transfers the entanglement to a 1588 nm photon. We characterize the resulting state by correlation measurements in different bases and find a lower bound to the Bell state fidelity of F = 0.77 +/- 0.03. This result presents an important step towards extending quantum networks via optical fiber infrastructure

Time-resolved optical microscopy of single gold nanoparticles

Abstract not available

Acoustic oscillations and elastic moduli of single gold nanorods

We present the first acoustic vibration measurements of single gold nanorods with well-characterized dimensions and crystal structure. The nanorods have an average size of 90 nm x 30 nm and display two vibration modes, the breathing mode and the extensional mode. Correlation between the dimensions obtained from electron microscope images and the vibrational frequencies of the same particle allows us to determine the elastic moduli for each individual nanorod. Contrary to previous reports on ensembles of gold nanorods, we find that the single particle elastic moduli agree well with bulk values

Damping of Acoustic Vibrations of Single Gold Nanoparticles Optically Trapped in Water

We combine ultrafast pump–probe spectroscopy with optical trapping to study homogeneous damping of the acoustic vibrations of single gold nanospheres (80 nm diameter) and nanorods (25 nm diameter by 60 nm length) in water. We find a significant particle-to-particle variation in damping times. Our results indicate that vibrational damping occurs not only by dissipation into the liquid, but also by damping mechanisms intrinsic to the particle. Our experiment opens the study of mechanisms of intrinsic mechanical dissipation in metals at frequencies 1–1000 GHz, a range that has been difficult to access thus far

Optical pump-probe spectroscopy of single gold nanoparticles

We have studied time-dependent optical properties of individual gold nanoparticles of different shapes with 10-100 nm sizes. Besides a fast electronic response, we find a number of vibrational modes whose frequency and damping times give information about the nanoenvironment of the particle and its coupling to a solid substrate