All-optical switching and strong coupling using tunable whispering-gallery-mode microresonators

We review our recent work on tunable, ultrahigh quality factor whispering-gallery-mode bottle microresonators and highlight their applications in nonlinear optics and in quantum optics experiments. Our resonators combine ultra-high quality factors of up to Q = 3.6 \times 10^8, a small mode volume, and near-lossless fiber coupling, with a simple and customizable mode structure enabling full tunability. We study, theoretically and experimentally, nonlinear all-optical switching via the Kerr effect when the resonator is operated in an add-drop configuration. This allows us to optically route a single-wavelength cw optical signal between two fiber ports with high efficiency. Finally, we report on progress towards strong coupling of single rubidium atoms to an ultra-high Q mode of an actively stabilized bottle microresonator.Comment: 20 pages, 24 figures. Accepted for publication in Applied Physics B. Changes according to referee suggestions: minor corrections to some figures and captions, clarification of some points in the text, added references, added new paragraph with results on atom-resonator interactio

The response of silicon carbide and boron carbide subjected to shock-release-reshock plate-impact experiments

This article presents experimental and computational results of silicon carbide (SiC) and boron carbide (B4C) subjected to shock-release-reshock plate-impact conditions. The significance of these tests is that they provide a measurement of the strength of ceramic after it has been permanently deformed (damaged) and then unloaded. The experiments use an impactor configured to produce an initial shock, followed by a release, followed by a second shock. The first shock loads the ceramic above the Hugoniot Elastic Limit (HEL-1) producing plastic deformation and damage. The release wave unloads the ceramic producing additional plastic deformation and damage. The second shock reloads the damaged ceramic to another Hugoniot stress state. The wave profile produced from the second shock produces another HEL (HEL-2), a direct measure of the strength of the damaged ceramic. Computations are used to analyze the experiments and determine the plastic strain produced during unloading and the strength of the ceramic in the second shock. Three tests are presented for SiC and three for B4C. The results indicate that SiC maintains its strength when strained to over 8% plastic strain, while B4C appears to lose strength after exceeding the HEL-1. It also appears that the process of unloading damaged ceramic does not affect the strength and/or the moduli for these two materials

The effect of water content on the shock compaction of sand

This work presents a series of two-dimensional mesoscale simulations in which the water content of sand was varied in order to assess the effect on the resulting bulk shock compaction behavior. The simulation results are compared to experimental data from a variety of sources. The mesoscale results compare favorably the experiments. In addition, the results indicate that dynamic fracture plays a key role in determining the overall compaction behavior of sand