Achromatic diffraction from polarization gratings with high efficiency

Oh, Chulwoo; Escuti, Michael J.

doi:10.1364/ol.33.002287

Cited by 296 publications

(180 citation statements)

References 14 publications

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“…Note, however, that leakage terms due to retardance offsets for both the half-wave vAPP optic and the quarter-wave plate limit the contrast performance (Snik et al 2012). In Otten et al (2014b), we introduced a simplified version of the vAPP (grating-vAPP or gvAPP) that includes a linear phase ramp (i.e., a "polarization grating"; Oh & Escuti 2008;Packham et al 2010) to impose the circular polarization splitting.…”

Section: The Grating-vapp Principlementioning

confidence: 99%

ON-SKY PERFORMANCE ANALYSIS OF THE VECTOR APODIZING PHASE PLATE CORONAGRAPH ON MagAO/Clio2

Otten

Snik

Kenworthy

et al. 2017

ApJ

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We report on the performance of a vector apodizing phase plate coronagraph that operates over a wavelength range of 2-5 μmand is installed in MagAO/Clio2 at the 6.5 m Magellan Clay telescope at Las Campanas Observatory, Chile. The coronagraph manipulates the phase in the pupil to produce three beams yielding two coronagraphic point-spread functions (PSFs) and one faint leakage PSF. The phase pattern is imposed through the inherently achromatic geometric phase, enabled by liquid crystal technology and polarization techniques. The coronagraphic optic is manufactured using a direct-write technique for precise control of the liquid crystal patternand multitwist retarders for achromatization. By integrating a linear phase ramp to the coronagraphic phase pattern, two separated coronagraphic PSFs are created with a single pupil-plane optic, which makes it robust and easy to install in existing telescopes. The two coronagraphic PSFs contain a 180°dark hole on each side of a star, and these complementary copies of the star are used to correct the seeing halo close to the star. To characterize the coronagraph, we collected a data set of a bright (m L =0-1) nearby star with ∼1.5 hr of observing time. By rotating and optimally scaling one PSFand subtracting it from the other PSF, we see a contrast improvement by 1.46 magnitudes at l D 3.5. With regular angular differential imaging at 3.9 μm, the MagAO vector apodizing phase plate coronagraph delivers a s D 5 mag contrast of 8.3 (= -10 3.3 ) at 2 l Dand 12.2 (= -10 4.8 ) at l D 3.5.

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Section: The Grating-vapp Principlementioning

confidence: 99%

ON-SKY PERFORMANCE ANALYSIS OF THE VECTOR APODIZING PHASE PLATE CORONAGRAPH ON MagAO/Clio2

Otten

Snik

Kenworthy

et al. 2017

ApJ

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“…The PGs employed here are members of the birefringent diffractive optical elements class [12][13][14] including spatially periodic birefringence effects, which are, in this case, realized using liquid crystal (LC) materials [14][15][16][17][18]. Individually, they act as a thinfilm beam splitter that is functionally analogous to a Wollaston prism.…”

Section: Channeled Imaging Polarimetry Using Polarization Gratingsmentioning

confidence: 99%

White-light channeled imaging polarimeter using broadband polarization gratings

et al. 2011

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A white-light snapshot channeled linear imaging (CLI) polarimeter is demonstrated by utilizing polarization gratings (PGs). The CLI polarimeter is capable of measuring the two-dimensional distribution of the linear Stokes polarization parameters by incorporating two identical PGs, in series, along the optical axis. In this configuration, the general optical shearing functionality of a uniaxial crystal-based Savart plate is realized. However, unlike a Savart plate, the diffractive nature of the PGs creates a linear dependence of the shear versus wavelength, thus providing broadband functionality. Consequently, by incorporating the PG-based Savart plate into a Savart plate channeled imaging polarimeter, white-light interference fringes can be generated. This enables polarimetric image data to be acquired at shorter exposure times in daylight conditions, making it more appealing over the quasi-monochromatic channeled imaging polarimeters previously described in the literature. Furthermore, the PG-based device offers significantly more compactness, field of view, optical simplicity, and vibration insensitivity than previously described white-light CLI polarimeters based on Sagnac interferometers. Included in this paper are theoretical descriptions of the linear (S 0 , S 1 , and S 2 ) and complete (S 0 , S 1 , S 2 , and S 3 ) channeled Stokes imaging polarimeters. Additionally, descriptions of our calibration procedures and our experimental proof of concept CLI system are provided. These are followed by laboratory and outdoor polarimetric measurements of S 0 , S 1 , and S 2 .

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“…In this way, a customized LC director distribution can be achieved to offer special designed optical functions. Many photonic devices can be achieved via patterned alignment, including patterned retarders [9,10], Q-plates [4,5], LC gratings [11,12], LC lenses [13][14][15], and polarization converters [16][17][18], etc., which could find many important applications in beam shaping [4], imaging system [13,14], Complementary Metal Oxide Semiconductor (CMOS) sensor system [19] and 3D display [10], etc.…”

Section: Introductionmentioning

confidence: 99%

Ferroelectric Liquid Crystal Dammann Grating by Patterned Photoalignment

et al. 2017

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Abstract:In this article, a ferroelectric liquid crystal (FLC) dammann grating (DG) is demonstrated based on the patterned photoalignment technology. By applying low electric field (10 V) on the FLC DG, the grating can switch between a diffractive state with 7 × 7 optical spots array and a non-diffractive state, depending on the polarity of electric field. The FLC DG shows very fast switching speed with switching on time and off time to be only 81 µs and 59 µs respectively. Comparing with other fast LC DGs such as the ones based on blue phase LC or dual-frequency LC, the switching speed of the proposed FLC DG is about one order faster, which provides great potential and perspective for the FLC DG to be applied in a broad range of optical applications such as optical communication and beam shaping.

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Achromatic diffraction from polarization gratings with high efficiency

Cited by 296 publications

References 14 publications

ON-SKY PERFORMANCE ANALYSIS OF THE VECTOR APODIZING PHASE PLATE CORONAGRAPH ON MagAO/Clio2

ON-SKY PERFORMANCE ANALYSIS OF THE VECTOR APODIZING PHASE PLATE CORONAGRAPH ON MagAO/Clio2

White-light channeled imaging polarimeter using broadband polarization gratings

Ferroelectric Liquid Crystal Dammann Grating by Patterned Photoalignment

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