8,121 research outputs found
The Photonic Lantern
Photonic lanterns are made by adiabatically merging several single-mode cores
into one multimode core. They provide low-loss interfaces between single-mode
and multimode systems where the precise optical mapping between cores and
individual modes is unimportant.Comment: 45 pages; article unchanged, accepted for publication in Advances in
Optics and Photonic
Optimizing astrophotonic spatial reformatters using simulated on-sky performance
One of the most useful techniques in astronomical instrumentation is image
slicing. It enables a spectrograph to have a more compact angular slit, whilst
retaining throughput and increasing resolving power. Astrophotonic components
like the photonic lanterns and photonic reformatters can be used to replace
bulk optics used so far. This study investigates the performance of such
devices using end-to-end simulations to approximate realistic on-sky
conditions. It investigates existing components, tries to optimize their
performance and aims to understand better how best to design instruments to
maximize their performance. This work complements the recent work in the field
and provides an estimation for the performance of the new components.Comment: Conference proceedings in SPIE 2018 Austin Texa
The Distance and Morphology of V723 Cassiopeiae (NOVA CASSIOPEIA 1995)
We present spatially resolved infrared spectra of V723 Cas (Nova Cassiopeia
1995) obtained over four years with the integral field spectrograph OSIRIS on
Keck II. Also presented are one epoch of spatially unresolved spectra from the
long slit spectrograph NIRSPEC on Keck II. The OSIRIS observations made use of
the laser guide star adaptive optics facility that produced diffraction-limited
spatial resolution of the strong coronal emission features in the nova ejecta.
We remove the point-like continuum from V723 Cas data cubes to reveal details
of the extended nebula and find that emission due to [Si VI] and [Ca VIII] has
an equatorial ring structure with polar nodules-a strikingly different
morphology than emission due to [Al IX], which appears as a prolate spheroid.
The contrast in structure may indicate separate ejection events. Using the
angular expansion and Doppler velocities observed over four epochs spaced at
one year intervals, we determine the distance to V723 Cas to be 3.85+0.23-0.21
kpc. We present the OSIRIS three-dimensional data here in many ways: as
narrowband images, one- and two-dimensional spectra, and a volume rendering
that reveals the true shape of the ejecta.Comment: 37 pages, 8 figure
Magnetic Control of Transmission and Helicity of Nano-Structured Optical Beams in Magnetoplasmonic Vortex Lenses
We theoretically investigate the generation of far-field propagating optical
beams with a desired orbital angular momentum by using an archetypical
magnetoplasmonic tip surrounded by a gold spiral slit. The use of a magnetic
material can lead to important implications once magneto-optical activity is
activated through the application of an external magnetic field. The physical
model and the numerical study presented here introduce the concept of
magnetically tunable plasmonic vortex lens, namely a magnetoplasmonic vortex
lens, which ensures a tunable selectivity in the polarization state of the
generated nanostructured beam. The presented system provides a promising
platform for a localized excitation of plasmonic vortices followed by their
beaming in the far-field with an active modulation of both light's
transmittance and helicity
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