ORBi: Karlsson Anders L - Three telescope nuller based on multibeam injection into single-mode waveguide

Reference : Three telescope nuller based on multibeam injection into single-mode waveguide


	Document type :	Scientific congresses and symposiums : Paper published in a book
	Discipline(s) :	Physical, chemical, mathematical & earth Sciences : Space science, astronomy & astrophysics
	To cite this reference:	http://hdl.handle.net/2268/78448

Title :	Three telescope nuller based on multibeam injection into single-mode waveguide
Language :	English
Author, co-author :	Karlsson, Anders L [> > > >]
	Wallner, Oswald [> > > >]
	Perdigues Armengol, Josep M [> > > >]
	Absil, Olivier [Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > Astroph. extragalactique et observations spatiales (AEOS) >]
Publication date :	1-Oct-2004
Main document title :	New Frontiers in Stellar Interferometry
Editor :	Traub, Wesley
Publisher :	SPIE
Collection and collection volume :	Proceedings of the SPIE, volume 5491
Pages :	831
Peer reviewed :	No
On invitation :	No
Audience :	International
City :	Bellingham
Country :	WA, USA
Event name :	New Frontiers in Stellar Interferometry
Event date :	du 24 au 31 mai 2006
Event organizer :	SPIE
Event place (city) :	Glasgow
Event country :	UK
Abstract :	[en] Nulling interferometry of exo-solar planets requires as a minimum two telescopes, of which one is phase shifted by 180 degrees, such that the on-axis stellar object is cancelled, while the light from the off-axis planet interferes constructively. Improvement of the nulling performance and the introduction of chopping leads to space interferometers of four or more telescopes and a separate spacecraft dedicated to beam recombination, as currently baselined for Darwin and TPF. It has recently been demonstrated that the stellar leaks mainly affects the integration times for near-by target stars [o,c]. Considering that there are only a few near-by targets and that the integrations times for each of these is short compared to that of distant stars, it appears advantageous to simplify the interferometer, by accepting higher levels of stellar leaks for near-by targets. A simple, chopping nulling interferometer can be obtained by adding one equal size telescope to the basic two telescope nulling interferometer. Modulation is obtained by applying time-varying phase-shifts to the beams before recombination, i.e. inherent modulation [d]. The recombination of 3 multi-axial beams is achieved by coupling into a single mode waveguide, leading to high modulation and coupling efficiencies, and a single focal plane [i]. Linear and circular telescope configurations are proposed and investigated, including a discussion on the need of a separate spacecraft for beam recombination. The associated transmission and modulation maps and efficiencies are calculated and discussed.
Target :	Researchers
Permalink :	http://hdl.handle.net/2268/78448
Other URL :	http://adsabs.harvard.edu/abs/2004SPIE.5491..831K

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	File	Commentary	Version	Size	Access
Open access	Three Telescope Nuller draft 1.13.pdf		Author preprint	362.52 kB	View/Open

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