3,965 research outputs found
Eigenmode in a misaligned triangular optical cavity
We derive relationships between various types of small misalignments on a
triangular Fabry-Perot cavity and associated geometrical eigenmode changes. We
focus on the changes of beam spot positions on cavity mirrors, the beam waist
position, and its angle. A comparison of analytical and numerical results shows
excellent agreement. The results are applicable to any triangular cavity close
to an isosceles triangle, with the lengths of two sides much bigger than the
other, consisting of a curved mirror and two flat mirrors yielding a waist
equally separated from the two flat mirrors. This cavity shape is most commonly
used in laser interferometry. The analysis presented here can easily be
extended to more generic cavity shapes. The geometrical analysis not only
serves as a method of checking a simulation result, but also gives an intuitive
and handy tool to visualize the eigenmode of a misaligned triangular cavity.Comment: 17 pages, 21 figure
Local Energy Gap in Deformed Carbon Nanotubes
The effects of graphite surface geometrical deformation on the dynamics of
conducting electrons are investigated theoretically. The analysis is performed
within the framework of a deformation-induced gauge field and corresponding
deformation-induced magnetic field. It is shown that the latter gives a local
energy gap along the axis of a deformed nanotube. We compare our energy gap
results with experimental data on energy gaps in nanotubes and peapods. We also
discuss the mixing of two Fermi points and construct a general model of low
energy dynamics, including a short-range deformation of the graphite sheet.
This model is equivalent to the Weyl equation in {\it U}(1) Abelian and {\it
SU}(2) non-Abelian deformation-induced gauge fields.Comment: 18 pages, 4 figures, corrected typos, added references, improved
presentation (v4, published version
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