Achromatic Eight-Octant Phase-Mask Coronagraph Using Photonic Crystal

Murakami, Naoshi; Nishikawa, Jun; Yokochi, Kaito; Tamura, Motohide; Baba, Naoshi; Abe, Lyu

doi:10.1088/0004-637x/714/1/772

Cited by 37 publications

(24 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Figure 2 suggests that the polarizer P1 discards half the incoming light from a target, if it is unpolarized. However, the observational efficiency can be improved by constructing a dualchannel coronagraph by replacing the polarizers with polarization-beam splitters, as proposed in the context of the eight-octant phase-mask coronagraph [38].…”

Section: Resultsmentioning

confidence: 99%

“…A manufacturing defect at the central phase singularity seems to be extremely small, probably less than 1 µm. We note that a similar photonic-crystal coronagraphic mask, an eight-octant phase mask, has been manufactured based on the same technology [38]. In the microscope image, we can also observe some dark spots, probably due to the measurement process (e.g., nonuniformity of the polarizers).…”

Section: Laboratory Demonstrationsmentioning

confidence: 90%

See 1 more Smart Citation

Design and laboratory demonstration of an achromatic vector vortex coronagraph

et al. 2013

Self Cite

View full text Add to dashboard Cite

Abstract:A vector vortex coronagraph (VVC) is one of promising means for imaging extremely faint objects around bright stars such as exoplanets. We present a design of an achromatic VVC, in which an axially-symmetric half-wave plate (AHP) is placed between crossed polarization filters (circular polarizer and analyzer). The circular polarizer and the analyzer are both composed of a polarizer and a quarter-wave plate (QWP). We demonstrate, via Jones calculus and Fourier analysis, that the achromatic stellar elimination can theoretically be realized by optimal polarization filters, even when chromatic AHP and QWPs are used. We carried out laboratory demonstrations of the designed VVC using a photonic-crystal AHP. As a result, we observed achromatic coronagraphic performance, a light suppression level of 7 × 10 −5 , over a wavelength from 543 nm to 633 nm.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Laboratory Demonstrationsmentioning

confidence: 90%

Design and laboratory demonstration of an achromatic vector vortex coronagraph

et al. 2013

Self Cite

View full text Add to dashboard Cite

show abstract

“…As described above, this mask provides the π-phase difference between light beams passing through the adjacent octant regions. From the SEM image, we can see that manufacturing defect is extremely small, which has been roughly estimated to be about 400 nm for a central singular point and about 100 nm for octant boundaries 13 .…”

Section: Photonic-crystal Coronagraph Masksmentioning

confidence: 97%

“…The polarization filtering will be a promising solution for broadening the operation spectral range of the coronagraph 14 . For realizing the achromatic coronagraphs, it has been proposed to use crossed linear polarizers for the 8OPM 5,13 , or circular polarizers for the VVC mask 15 . …”

Section: Photonic-crystal Coronagraph Masksmentioning

confidence: 99%

Coronagraph focal-plane phase masks based on photonic crystal technology: recent progress and observational strategy

Murakami

Nishikawa

Traub

et al. 2012

Space Telescopes and Instrumentation 2012: Optical, Infrared, and Millimeter Wave

Self Cite

View full text Add to dashboard Cite

Photonic crystal, an artificial periodic nanostructure of refractive indices, is one of the attractive technologies for coronagraph focal-plane masks aiming at direct imaging and characterization of terrestrial extrasolar planets. We manufactured the eight-octant phase mask (8OPM) and the vector vortex coronagraph (VVC) mask very precisely using the photonic crystal technology. Fully achromatic phase-mask coronagraphs can be realized by applying appropriate polarization filters to the masks. We carried out laboratory experiments of the polarization-filtered 8OPM coronagraph using the High-Contrast Imaging Testbed (HCIT), a state-of-the-art coronagraph simulator at the Jet Propulsion Laboratory (JPL). We report the experimental results of 10 -8 -level contrast across several wavelengths over 10% bandwidth around 800nm. In addition, we present future prospects and observational strategy for the photonic-crystal mask coronagraphs combined with differential imaging techniques to reach higher contrast. We proposed to apply the polarization-differential imaging (PDI) technique to the VVC, in which we built a two-channel coronagraph using polarizing beam splitters to avoid a loss of intensity due to the polarization filters. We also proposed to apply the angular-differential imaging (ADI) technique to the 8OPM coronagraph. The 8OPM/ADI mode mitigates an intensity loss due to a phase transition of the mask and provides a full field of view around central stars. We present results of preliminary laboratory demonstrations of the PDI and ADI observational modes with the phase-mask coronagraphs.

show abstract

“…Following the successful experience of the 8-octant phase-mask coronagraph made out of photonics crystal, 24 a VVC was made and tested at the Hokkaido University.…”

Section: Visible Vvc Made Out Of Photonics Crystalsmentioning

confidence: 99%

Taking the vector vortex coronagraph to the next level for ground- and space-based exoplanet imaging instruments: review of technology developments in the USA, Japan, and Europe

et al. 2011

Self Cite

View full text Add to dashboard Cite

The Vector Vortex Coronagraph (VVC) is one of the most attractive new-generation coronagraphs for ground-and space-based exoplanet imaging/characterization instruments, as recently demonstrated on sky at Palomar and in the laboratory at JPL, and Hokkaido University. Manufacturing technologies for devices covering wavelength ranges from the optical to the mid-infrared, have been maturing quickly. We will review the current status of technology developments supported by NASA in the USA (Jet Propulsion Laboratory-California Institute of Technology, University of Arizona, JDSU and BEAMCo), Europe (University of Liège, Observatoire de ParisMeudon, University of Uppsala) and Japan (Hokkaido University, and Photonics Lattice Inc.), using liquid crystal polymers, subwavelength gratings, and photonics crystals, respectively. We will then browse concrete perspectives for the use of the VVC on upcoming ground-based facilities with or without (extreme) adaptive optics, extremely large ground-based telescopes, and space-based internal coronagraphs.

show abstract

Achromatic Eight-Octant Phase-Mask Coronagraph Using Photonic Crystal

Cited by 37 publications

References 35 publications

Design and laboratory demonstration of an achromatic vector vortex coronagraph

Design and laboratory demonstration of an achromatic vector vortex coronagraph

Coronagraph focal-plane phase masks based on photonic crystal technology: recent progress and observational strategy

Taking the vector vortex coronagraph to the next level for ground- and space-based exoplanet imaging instruments: review of technology developments in the USA, Japan, and Europe

Contact Info

Product

Resources

About