Shaft Resistance During Driving in Clay from Laboratory Tests

This paper presents a laboratory study which aimed at investigating the soil/pile interaction during driving. A short review of past experimental works justifies the need for more consistent data. The test equipment (a rod driven through a sample of soil) is briefly presented and some signals are displayed to illustrate the quality of the measurements. The tests were performed on samples of normally consolidated Kaolinit clay. The analysis of the stress waves propagating in the rod, during driving, provided a good estimation of interaction forces, bar velocities and displacements of the pile model in the sample. Relationships were established between the interaction force, the energy dissipated in the sample of soil, the velocity and the displacement of the rod, and the confining pressure of the sample. Observations and relationships were used (1) to identify the physical phenomena occurring at the soil/pile interface during driving, and (2) to base a law governing this shaft interaction

ICP polishing of silicon for high quality optical resonators on a chip

Miniature concave hollows, made by wet etching silicon through a circular mask, can be used as mirror substrates for building optical micro-cavities on a chip. In this paper we investigate how ICP polishing improves both shape and roughness of the mirror substrates. We characterise the evolution of the surfaces during the ICP polishing using white-light optical profilometry and atomic force microscopy. A surface roughness of 1 nm is reached, which reduces to 0.5 nm after coating with a high reflectivity dielectric. With such smooth mirrors, the optical cavity finesse is now limited by the shape of the underlying mirror

Arrays of waveguide-coupled optical cavities that interact strongly with atoms

We describe a realistic scheme for coupling atoms or other quantum emitters with an array of coupled optical cavities. We consider open Fabry-Perot microcavities coupled to the emitters. Our central innovation is to connect the microcavities to waveguide resonators, which are in turn evanescently coupled to each other on a photonic chip to form a coupled cavity chain. In this paper, we describe the components, their technical limitations and the factors that need to be determined experimentally. This provides the basis for a detailed theoretical analysis of two possible experiments to realize quantum squeezing and controlled quantum dynamics. We close with an outline of more advanced applications.Comment: 30 pages, 8 figures. Submitted to New Journal of Physic

Out-of-equilibrium physics in driven dissipative coupled resonator arrays

Coupled resonator arrays have been shown to exhibit interesting many- body physics including Mott and Fractional Hall states of photons. One of the main differences between these photonic quantum simulators and their cold atoms coun- terparts is in the dissipative nature of their photonic excitations. The natural equi- librium state is where there are no photons left in the cavity. Pumping the system with external drives is therefore necessary to compensate for the losses and realise non-trivial states. The external driving here can easily be tuned to be incoherent, coherent or fully quantum, opening the road for exploration of many body regimes beyond the reach of other approaches. In this chapter, we review some of the physics arising in driven dissipative coupled resonator arrays including photon fermionisa- tion, crystallisation, as well as photonic quantum Hall physics out of equilibrium. We start by briefly describing possible experimental candidates to realise coupled resonator arrays along with the two theoretical models that capture their physics, the Jaynes-Cummings-Hubbard and Bose-Hubbard Hamiltonians. A brief review of the analytical and sophisticated numerical methods required to tackle these systems is included.Comment: Chapter that appeared in "Quantum Simulations with Photons and Polaritons: Merging Quantum Optics with Condensed Matter Physics" edited by D.G.Angelakis, Quantum Science and Technology Series, Springer 201

Photon condensation in circuit QED by engineered dissipation

We study photon condensation phenomena in a driven and dissipative array of superconducting microwave resonators. Specifically, we show that by using an appropriately designed coupling of microwave photons to superconducting qubits, an effective dissipative mechanism can be engineered, which scatters photons towards low-momentum states while conserving their number. This mimics a tunable coupling of bosons to a low temperature bath, and leads to the formation of a stationary photon condensate in the presence of losses and under continuous-driving conditions. Here we propose a realistic experimental setup to observe this effect in two or multiple coupled cavities, and study the characteristics of such an out-of-equilibrium condensate, which arise from the competition between pumping and dissipation processes

Super-resolution STED microscopy advances with yellow CW OPSL

Researchers have a growing need to push optical microscopy beyond the diffraction limit to answer key questions in biology, and stimulated emission depletion (STED) has proven to be a fluorescence imaging technique that can accomplish this goal. Biologists are currently seeking to connect molecular behavior to macroscopic behavior, determining how cells signal with each other, and how signaling at the cellular/organism level is then relayed back to DNA/RNA level control to regulate single genes. A STED nanoscope uses two laser beams. The first is the excitation laser, which as in confocal microscopy is usually focused to a near-diffraction-limited spot within a fluorescently labeled sample. The excitation wavelength of this laser is chosen to match the absorption peak of the target fluorophore. When applying a high enough STED laser power above a certain threshold, all the excited fluorophores in the path of the STED beam emit at the STED wavelength making them unavailable for fluorescence

Demonstration of UV-written waveguides, Bragg gratings and cavities at 780 nm, and an original experimental measurement of group delay

We present direct UV-written waveguides and Bragg gratings operating at 780 nm. By combining two gratings into a Fabry-Perot cavity we have devised and implemented a novel and practical method of measuring the group delay of Bragg gratings

The last millennia history of detrital sedimentation in the Lower Seine Valley (Normandy, NW France): review

International audiencePost-glacial climate changes and sea-level fluctuations have strongly influenced N-W European environments and sedimentation. To these natural events, increasing anthropogenic pressure has to be added. Forest clearance and agricultural development are the main factors responsible for the erosional processes in Northwest Europe. This article analyses Holocene sequences of the Lower Seine Valley (LSV) (Paris Basin) to understand better the origin of detrital and terrigenous input and how much humans have contributed to it. Three main sectors of the LSV are analysed: estuarine, fluvial and tributaries. Since Neolithic times, there are seven erosional phases that can be identified and essentially linked to human pressure

Elementary array of Fabry-Pérot waveguide resonators with tunable coupling

We recently proposed that an array of optical cavities containing quantum emitters could be interconnected by an optical bus made of Fabry Pérot resonators lying side by side, for applications in quantum information processing and quantum simulation. Here, we demonstrate the feasibility of this geometry. We show that the resonators can be conveniently coupled, and that the coupling rate between adjacent waveguides can be widely tuned using the thermo-optic effect. The device is linearly scalable and can be combined with other integrated devices, making it more generally applicable as an adjustable optical delay line or optical interconnect

Field trial of a quantum secured 10Gb/s DWDM transmission system over a single installed fiber

We present results from the first field-trial of a quantum-secured DWDM transmission system, in which quantum key distribution (QKD) is combined with 4 x 10Gb/s encrypted data and transmitted simultaneously over 26km of field installed fiber. QKD is used to frequently refresh the key for AES-256 encryption of the 10Gb/s data traffic. Scalability to over 40 DWDM channels is analyzed