1) We demonstrate a compact, planar-optic approach for the generation of accelerating near-IR laser pulses by illuminating metasurfaces consisting of plasmonic nanoantennas patterned onto a glass substrate. Two accelerating beam trajectories were generated within the glass and imaged onto a CCD; close agreement is shown with theory. The simplicity and compactness of the proposed planar-optics approach to generating accelerating beams opens new opportunities in the realization of accelerating beams and related devices for advanced manipulation of light.
2) Coherent control of quantum dots has been intensively investigated for fundamental interest in physics as well as potential applications. While there are a lot of advantages for using an ensemble of quantum dots, most of studies have been conducted by using single quantum dots due to the technical difficulties. In this talk, I will discuss the experimental demonstration which clearly reveals coherent evolution in the exciton/biexciton system in an InAs self-assmebled quatum dot ensemble [1]. I will first talk about the experimental technique, the pre-pulse two-dimensional spectroscopy, used to observe the coherent evolution in the ensemble system. I will then talk about the experimental results revealing coherent manipulation of exciton and biexciton population by the pre-pulse. Lastly, I will discuss the detuning and trions’ effects, which two dimensional coherent spectroscopy can successfully elucidate.

[1] Takeshi Suzuki, Rohan Singh, Manfred Beyer, Arne Ludwig, Andreas D. Wieck, and Steven T. Cundiff, Phys. Rev. Lett., in press.