596 research outputs found
Fabrication of a microresonator-fiber assembly maintaining a high-quality factor by CO2 laser welding
We demonstrate fabrication of a microtoroid resonator of a high-quality
(high-Q) factor using femtosecond laser three-dimensional (3D) micromachining.
A fiber taper is reliably assembled to the microtoroid using CO2 laser welding.
Specifically, we achieve a high Q-factor of 2.12*10^6 in the
microresonator-fiber assembly by optimizing the contact position between the
fiber taper and the microtoroid.Comment: 7 pages, 5 figure
Five-dimensional generalized gravity with curvature-matter coupling
The generalized gravity with curvature-matter coupling in
five-dimensional (5D) spacetime can be established by assuming a
hypersurface-orthogonal spacelike Killing vector field of 5D spacetime, and it
can be reduced to the 4D formulism of FRW universe. This theory is quite
general and can give the corresponding results to the Einstein gravity,
gravity with both no-coupling and non-minimal coupling in 5D spacetime as
special cases, that is, we would give the some new results besides previous
ones given by Ref.\cite{60}. Furthermore, in order to get some insight into the
effects of this theory on the 4D spacetime, by considering a specific type of
models with and , we not
only discuss the constraints on the model parameters , , but also
illustrate the evolutionary trajectories of the scale factor , the
deceleration parameter and the scalar field , in
the reduced 4D spacetime. The research results show that this type of
gravity models given by us could explain the current accelerated expansion of
our universe without introducing dark energy.Comment: arXiv admin note: text overlap with arXiv:0912.4581,
arXiv:gr-qc/0411066 by other author
On-chip electro-optic tuning of a lithium niobate microresonator with integrated in-plane microelectrodes
We demonstrate electro-optic tuning of an on-chip lithium niobate
microresonator with integrated in-plane microelectrodes. First two metallic
microelectrodes on the substrate were formed via femtosecond laser process.
Then a high-Q lithium niobate microresonator located between the
microelectrodes was fabricated by femtosecond laser direct writing accompanied
by focused ion beam milling. Due to the efficient structure designing, high
electro-optical tuning coefficient of 3.41 pm/V was observed.Comment: 6 pages, 3 figure
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