eiscat 3d workshop, uppsala, 19 – 21 may 2010 the lois project part of the nature online...

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).

11

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

12

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

15

The James Webb Space Telescope

Credit: ESA (C. Carreau)

EISCAT_3D Workhop. Uppsala, 19 – 21 May 2010

Field vector sensing means total configurability

16

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

17

1

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

2

1

23

4

OVC Lyot stop ordinary Lyot stop

EISCAT_3D Workhop. Uppsala, 19 – 21 May 2010

First OVC @ T122 Asiago telescope

19

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