Denis Defrère,
University of Arizona
O. Absil, P.-‐A. Absil, P. Baudoz, B. Carlomagno, C. Delacroix, V. Chris?aens, P. Forsberg, J. Girard, C. Gomez Gonzalez, S. Habraken, P. Hinz, E. Huby, A. Jolivet, M. Karlsson, D. Mawet, J. Milli, E. Pan?n,
P. Piron, G. Ruane, E. Serabyn, J. Surdej, M. Van Droogenbroeck, E. Vargas Catalan, and O. Wertz
Direct exoplanet imaging with
Pathways to habitable planets II, July 2015, Bern
Which planets?
2
current imaging surveys
EL T VL T /L BT
The birth of a concept
•
FQPM à
sub-‐wavelength gra?ngs
à
Annular Groove PM
•
Advantages of the AGPM
o
Inner working angle ≈ 1 λ/D
o
Clear 360° discovery space
o
Achroma?c (SG design)
o
Easy to implement
0
0
π
π
Mawet, Riaud, Absil & Surdej 2005
2003
2005
π π π π 0 0 0 0Pathways to habitable planets II, July 2015, Bern
Grating design/optimization
Lo
g(n
ull
d
ep
th
)
-4 -3 -2 3.5 3.6 3.7 3.8 3.9 4.0 4.1Log(null depth)
Delacroix et al. 2013
Etching on synthetic diamond
•
Inductively coupled plasma etching
o
N band (gra?ng period = 4.6 µm)
o
L band (gra?ng period = 1.4 µm)
o Parameters close to
•
Parameters close to op?mal … need to test!
N band (Nov 2009)
N band (Feb 2012)
L band (Sep 2012)
1.4
µm
Forsberg & Karlsson 2013
4.7 µm
4.6
Pathways to habitable planets II, July 2015, Bern
Setting up the bench
“Yacadire” @ Paris-Meudon
High performance
1
10
100
1000
Pe
ak
re
je
c4
on
L band
Pathways to habitable planets II, July 2015, Bern
Installation at VLT, LBT, and Keck
Installation at VLT, LBT, and Keck
Don’t
break a
priceless
Pathways to habitable planets II, July 2015, Bern
ScientiIic exploitation
10
Skemer et al. 2014NACO: science demonstration
Raw image of
β
Pic
Post-processed image
Pathways to habitable planets II, July 2015, Bern
Sensitivity to inner planets
β
Pic b
New
discovery
space
12
Absil et al. 2013 & Mawet et al. 2014The
β
Pic disk at L band
•
Warped, inner component
o
Disk detected down to 10 AU (0.4”)
•
Spine offset and bowed (anisotropic scajering)
50 AU
PA=29°
Pathways to habitable planets II, July 2015, Bern
VISIR: science demonstration
Delacroix et al. in prep
First light with LBT/LMIRCam
Peak rejection ~35:1
(far from optimal)
Pathways to habitable planets II, July 2015, Bern
First light with LBT/LMIRCam
Preliminary sliding PCA data reduction, not throughput-corrected (courtesy J. Kuhn, JPL/Caltech)
16
First light with Keck/NIRC2
~50:1 peak starlight
rejection, limited by
AO correction, and
Keck pupil
obscuration
Pathways to habitable planets II, July 2015, Bern
Prospects
Preliminary sliding PCA data reduction, not throughput-corrected (courtesy J. Kuhn)
18
•
Extension to shorter wavelengths (first K-‐band components recently
etched)
•
Extension to higher topological charges (trade some IWA for bejer
resilience to poin?ng jijer)
•
Combine the vortex with pupil-‐plane apodiza?on (phase and/or
amplitude)
•
M-‐dwarf survey
•
Protoplanets in transi?on disks
Charge-‐4 vortices for ELTs
transmission
charge-2
Pathways to habitable planets II, July 2015, Bern
