TY  - JOUR
A1  - Dikovsky, V.
A1  - Japha, Y.
A1  - Henkel, Carsten
A1  - Folman, R.
T1  - Reduction of magnetic noise in atom chips by material optimization
N2  - We discuss the influence of the material type in metal wires to the electromagnetic fluctuations in magnetic microtraps close to the surface of an atom chip. We show that significant reduction of the magnetic noise can be achieved by replacing the pure noble metal wires with their dilute alloys. The alloy composition provides an additional degree of freedom which enables a, controlled reduction of both magnetic noise and resistivity if the atom chip is cooled. In addition, we provide a careful re-analysis of the magnetically induced trap loss observed by Yu-Ju Lin et al. [Phys. Rev. Lett. 92 050404 (2004)] and find good agreement with an improved theory
Y1  - 2005
ER  - 
TY  - JOUR
A1  - Henkel, Carsten
T1  - Nanometer scala electromagnetic field fluctuations accepted for publication
Y1  - 2005
SN  - 1-588-83042-X
ER  - 
TY  - JOUR
A1  - Henkel, Carsten
T1  - Magnetostatic field noise near metallic surfaces
N2  - We develop an effective low-frequency theory of the electromagnetic field in equilibrium with thermal objects. The aim is to compute thermal magnetic noise spectra close to metallic microstructures. We focus on the limit where the material response is characterised by the electric conductivity. At the boundary between empty space and metallic microstructures, a large jump occurs in the dielectric function which leads to a partial screening of low-frequency magnetic fields generated by thermal current fluctuations. We resolve a, discrepancy between two approaches used in the past to compute magnetic field noise spectra close to microstructured materials
Y1  - 2005
ER  - 
TY  - JOUR
A1  - Henkel, Carsten
A1  - Joulain, Karl
T1  - Casimir force between designed materials : what is possible and what not
N2  - We establish strict upper limits for the Casimir interaction between multilayered structures of arbitrary dielectric or diamagnetic materials. We discuss the appearance of different power laws due to frequency-dependent material constants. Simple analytical expressions are in good agreement with numerical calculations based on Lifshitz theory. We discuss the improvements required for current ( meta) materials to achieve a repulsive Casimir force
Y1  - 2005
SN  - 0295-5075
ER  - 
TY  - JOUR
A1  - Kalkbrenner, T.
A1  - Hakanson, U.
A1  - Schadle, A.
A1  - Burger, S.
A1  - Henkel, Carsten
A1  - Sandoghdar, Vahid
T1  - Optical microscopy via spectral modifications of a nanoantenna
N2  - The existing optical microscopes form an image by collecting photons emitted from an object. Here we report on the experimental realization of microscopy without the need for direct optical communication with the sample. To achieve this, we have scanned a single gold nanoparticle acting as a nanoantenna in the near field of a sample and have studied the modification of its intrinsic radiative properties by monitoring its plasmon spectrum
Y1  - 2005
SN  - 0031-9007
ER  - 
TY  - JOUR
A1  - Zhang, B.
A1  - Henkel, Carsten
A1  - Haller, E.
A1  - Wildermuth, S.
A1  - Hofferberth, S.
A1  - Kruger, P.
A1  - Schmiedmayer, Jörg
T1  - Relevance of sub-surface chip layers for the lifetime of magnetically trapped atoms
N2  - We investigate the lifetime of magnetically trapped atoms above a planar, layered atom chip structure. Numerical calculations of the thermal magnetic noise spectrum are performed, based on the exact magnetic Green function and multi layer reflection coefficients. We have performed lifetime measurements where the center of a side guide trap is laterally shifted with respect to the current carrying wire using additional bias fields. Comparing the experiment to theory, we find a fair agreement and demonstrate that for a chip whose topmost layer is metallic, the magnetic noise depends essentially on the thickness of that layer, as long as the layers below have a, much smaller conductivity; essentially the same magnetic noise would be obtained with a metallic membrane suspended in vacuum. Based on our theory we give general scaling laws of how to reduce the effect of surface magnetic noise on the trapped atoms
Y1  - 2005
ER  -