the lois project part of the nature online collaboration
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The LOIS project Part of the Nature OnLine collaboration. Bo Thidé Swedish Institute of Space Physics, IRF, Uppsala, Sweden With contributions from the LOIS OAM/radio topology collaboration. - PowerPoint PPT PresentationTRANSCRIPT
EISCAT 3D workshop, Uppsala, 19 – 21 May 2010
The LOIS projectPart of the Nature OnLine collaboration
Bo ThidéSwedish Institute of Space Physics, IRF, Uppsala, Sweden
With contributions from the LOIS OAM/radio topology collaboration
EISCAT_3D Workhop. Uppsala, 19 – 21 May 2010
LOIS vector radio facilities in southern Sweden and labs in Uppsala for OAM radio and radar system assessments
Bo Thidé 2
Computer cluster (funded by two Shared University Research grants from IBM)
The control room at the LOIS Test Station Risinge/Växjö.
9m×8m×6m antenna chamber, Ångström Lab, Uppsala
Magnetometer, LOIS Test Station, Risinge/Växjö
Radio Sweden’s transmitter located about 100 km south of the Växjö LOIS test station and 100 km south-west of the Ronneby prototype station site. Will be used for space radar tests.
EISCAT_3D Workhop. Uppsala, 19 – 21 May 2010Bo Thidé 3
LOIS radio idea: Sample the entire field vectors in time and space (LOIS stn true superset of LOFAR stn)
EISCAT_3D Workhop. Uppsala, 19 – 21 May 2010
LOIS prototype station under construction in RonnebyTo be augmented by two outer, concentric rings, with 16 and 24 radio units,
respectively, for a total of 48 units with three dipoles each (consortium funding)
Bo Thidé 4
EISCAT_3D Workhop. Uppsala, 19 – 21 May 2010Bo Thidé 5REAL Seminar, BTH, Ronneby, 23 January, 2009
LOIS prototype station site at Angelskog, RonnebyLeft photos taken 21 December, 2007, at 14:00 local time. Right photo from eniro.se
EISCAT_3D Workhop. Uppsala, 19 – 21 May 2010Bo Thidé 6Swedish LOFAR Science Meeting, Stockholm, 15 January, 2009
LOIS prototype station centre at BTH in Ronneby
Eight ex-SWEGRID PC blades provided by UPPMAX, Uppsala University (SNIC/VR)
21/101 Gbit/s light path provided by theBlekinge Institute of Technology (BTH)
EISCAT_3D Workhop. Uppsala, 19 – 21 May 2010Bo Thidé 7
Use three orthogonal electric and magnetic antennas to sample the entire EM field vector
To be tried at EISCAT, 2010
EISCAT_3D Workhop. Uppsala, 19 – 21 May 2010
3D vector sensing allows new radio diagnostics Better SNR, polarisation in real time, DOA,…
Bo Thidé 8
Click on pictures for animation! Real data from a real, live outdoor vector receiver at Ångström Lab in Uppsala. On line since 2003.
Vector coherency gives superior SNR relative to conventional scalar intensity
Instantaneous wave polarisation from one single vector antenna
Bo Thidé 9Swedish LOFAR Science Meeting, Stockholm, 15 January, 2009
2D LOFAR/SKA-type interferometers exhibit polarisation aberration. 3D interferometers do not
EISCAT_3D Workhop. Uppsala, 19 – 21 May 2010Bo Thidé 10
Close collaboration with IBM Research, NY, on the analysis of streaming data from digital radio sensors
EISCAT_3D Workhop. Uppsala, 19 – 21 May 2010
Fork holograms are an example of such devices. If the hologram presents N bifurcations, then at the m-th diffraction order it imposes a OAM value equal to N m ħ (Vaziri et al. 2002).
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The generation of beams carrying OAM proceeds thanks to the insertion in the optical path of a phase modifying device which imprints a certain vorticity on the phase distribution of the incident beam.
l n
s
s = total thickness of the plate, Δn = difference of refraction indices.
Imparting OAM onto a light beam
Spiral Phase Plate
On-axis off-axis spectrum of OAM
EISCAT_3D Workhop. Uppsala, 19 – 21 May 2010
Properties of radio OAM generated by antenna arrays
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Thidé et al., Phys. Rev. Lett., 99, 087701, 2007
EISCAT_3D Workhop. Uppsala, 19 – 21 May 2010
Theory predicts that a circular polarised radio beam in a pure OAM eigenstate with azimuthal phase dependence exp(ilφ), frequency ω, and energy H, should have a total angular momentum component Jz
EM = lH/ω along the z (beam) axis.
Bo Thidé 13
The OAM radio results agree with theory
EISCAT_3D Workhop. Uppsala, 19 – 21 May 2010
Exchange of OAM between plasma and radio/radar
Bo Thidé 14
Brillouin = ion lineRaman = plasma line
EISCAT_3D Workhop. Uppsala, 19 – 21 May 2010
Improving resolving power of telescopes by one order of magnitude
Super Resolution with OVs in diffraction-limited telescopesand other optical instruments
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The James Webb Space Telescope
Credit: ESA (C. Carreau)
EISCAT_3D Workhop. Uppsala, 19 – 21 May 2010
Field vector sensing means total configurability
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The ultimate radio coronagraph!
EISCAT_3D Workhop. Uppsala, 19 – 21 May 2010
OV manipulation for detection at the telescope. Producing Optical Vortices with starlight and
the problem of atmospheric seeing
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EISCAT_3D Workhop. Uppsala, 19 – 21 May 2010
Optical Vortices and Stellar Coronagraphy
We place the phase mask in the focal plane of the telescope to generate an ℓ = 2 OV with the on-axis star, then followed by a ring-shaped Lyot stop to block that vortex. The off-axis secondary star light, instead, will pass through the Lyot mask without being affected.
Pictures taken@the Lyot mask position of two artificial stars with increasing angular distance
Fabrizio Tamburini Uppsala, Celsius Workshop 2010 18
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OVC Lyot stop ordinary Lyot stop
EISCAT_3D Workhop. Uppsala, 19 – 21 May 2010
First OVC @ T122 Asiago telescope
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2.8x10-10 (b)2-3 /D (a)
2-8 /D (a)
4-5 /D (a)
9.3x10-11 (b)
6.4x10-11 (b)
Theoretical contrast for a monochromatic source (b) versus the separation (a). Sufficient resolution for direct detection of extra-solar planets.
EISCAT_3D Workhop. Uppsala, 19 – 21 May 2010Bo Thidé 20
Supporting Sardinia Radio Telescope for OAM