230 research outputs found
Progress in atom chips and the integration of optical microcavities
We review recent progress at the Centre for Cold Matter in developing atom
chips. An important advantage of miniaturizing atom traps on a chip is the
possibility of obtaining very tight trapping structures with the capability of
manipulating atoms on the micron length scale. We recall some of the pros and
cons of bringing atoms close to the chip surface, as is required in order to
make small static structures, and we discuss the relative merits of metallic,
dielectric and superconducting chip surfaces. We point out that the addition of
integrated optical devices on the chip can enhance its capability through
single atom detection and controlled photon production. Finally, we review the
status of integrated microcavities that have recently been demonstrated at our
Centre and discuss their prospects for future development.Comment: 12 pages, 6 figures, proceedings of the ICOLS07 conferenc
Atom detection and photon production in a scalable, open, optical microcavity
A microfabricated Fabry-Perot optical resonator has been used for atom
detection and photon production with less than 1 atom on average in the cavity
mode. Our cavity design combines the intrinsic scalability of microfabrication
processes with direct coupling of the cavity field to single-mode optical
waveguides or fibers. The presence of the atom is seen through changes in both
the intensity and the noise characteristics of probe light reflected from the
cavity input mirror. An excitation laser passing transversely through the
cavity triggers photon emission into the cavity mode and hence into the
single-mode fiber. These are first steps towards building an optical
microcavity network on an atom chip for applications in quantum information
processing.Comment: 4 pages, 4 figures. A typographical error in the published paper has
been corrected (equation of the corrected normalized variance, page 3, 2nd
paragraph
Microfabricated high-finesse optical cavity with open access and small volume
We present a microfabricated optical cavity, which combines a very small mode volume with high finesse. In contrast to other micro-resonators, such as microspheres, the structure we have built gives atoms and molecules direct access to the high-intensity part of the field mode, enabling them to interact strongly with photons in the cavity for the purposes of detection and quantum-coherent manipulation. Light couples directly in and out of the resonator through an optical fiber, avoiding the need for sensitive coupling optics. This renders the cavity particularly attractive as a component of a lab-on-a-chip, and as a node in a quantum network
Atomic Bloch-Zener oscillations for sensitive force measurements in a cavity
Cold atoms in an optical lattice execute Bloch-Zener oscillations when they
are accelerated. We have performed a theoretical investigation into the case
when the optical lattice is the intra-cavity field of a driven Fabry-Perot
resonator. When the atoms oscillate inside the resonator, we find that their
back-action modulates the phase and intensity of the light transmitted through
the cavity. We solve the coupled atom-light equations self-consistently and
show that, remarkably, the Bloch period is unaffected by this back-action. The
transmitted light provides a way to observe the oscillation continuously,
allowing high precision measurements to be made with a small cloud of atoms.Comment: 5 pages, 2 figures. Updated version including cavity heating effect
A three-dimensional electrostatic actuator with a locking mechanism for a new generation of atom chips
A micromachined three-dimensional electrostatic actuator that is optimized for aligning and tuning optical microcavities on atom chips is presented. The design of the 3D actuator is outlined in detail, and its characteristics are verified by analytical calculations and finite element modelling. Furthermore, the fabrication process of the actuation device is described and preliminary fabrication results are shown. The actuation in the chip plane which is used for mirror positioning has a working envelope of 17.5 ?m. The design incorporates a unique locking mechanism which allows the out-of-plane actuation that is used for cavity tuning to be carried out once the in-plane actuation is completed. A maximum translation of 7 ?m can be achieved in the out-of-plane direction
Fabrication of micromirrors with pyramidal shape using anisotropic etching of silicon
Gold micro-mirrors have been formed in silicon in an inverted pyramidal shape. The pyramidal structures are created in the (100) surface of a silicon wafer by anisotropic etching in potassium hydroxide. High quality micro-mirrors are then formed by sputtering gold onto the smooth silicon (111) faces of the pyramids. These mirrors show great promise as high quality optical devices suitable for integration into MOEMS systems
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