Precise and diffraction-limited waveguide-to-free-space focusing gratings

Abstract We present the design and characterization of waveguide grating devices that couple visible-wavelength light at λ = 674 nm from single-mode, high index-contrast dielectric waveguides to free-space beams forming micron-scale diffraction-limited spots a designed distance and angle from the gr...

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Autores principales: Karan K. Mehta, Rajeev J. Ram
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Lenguaje:EN
Publicado: Nature Portfolio 2017
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Acceso en línea:https://doaj.org/article/203fc8a317a24223afdb09cdf9a0f811
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spelling oai:doaj.org-article:203fc8a317a24223afdb09cdf9a0f8112021-12-02T11:51:03ZPrecise and diffraction-limited waveguide-to-free-space focusing gratings10.1038/s41598-017-02169-22045-2322https://doaj.org/article/203fc8a317a24223afdb09cdf9a0f8112017-05-01T00:00:00Zhttps://doi.org/10.1038/s41598-017-02169-2https://doaj.org/toc/2045-2322Abstract We present the design and characterization of waveguide grating devices that couple visible-wavelength light at λ = 674 nm from single-mode, high index-contrast dielectric waveguides to free-space beams forming micron-scale diffraction-limited spots a designed distance and angle from the grating. With a view to application in spatially-selective optical addressing, and in contrast to previous work on similar devices, deviations from the main Gaussian lobe up to 25 microns from the focus and down to the 5 × 10−6 level in relative intensity are characterized as well; we show that along one dimension the intensity of these weak sidelobes approaches the limit imposed by diffraction from the finite field extent in the grating region. Additionally, we characterize the polarization purity in the focal region, observing at the center of the focus a low impurity <3 × 10−4 in relative intensity. Our approach allows quick, intuitive design of devices with such performance, which may be applied in trapped-ion quantum information processing and generally in any systems requiring optical routing to or from objects 10 s–100 s of microns from a chip surface, but benefitting from the parallelism and density of planar-fabricated dielectric integrated optics.Karan K. MehtaRajeev J. RamNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 7, Iss 1, Pp 1-8 (2017)
institution DOAJ
collection DOAJ
language EN
topic Medicine
R
Science
Q
spellingShingle Medicine
R
Science
Q
Karan K. Mehta
Rajeev J. Ram
Precise and diffraction-limited waveguide-to-free-space focusing gratings
description Abstract We present the design and characterization of waveguide grating devices that couple visible-wavelength light at λ = 674 nm from single-mode, high index-contrast dielectric waveguides to free-space beams forming micron-scale diffraction-limited spots a designed distance and angle from the grating. With a view to application in spatially-selective optical addressing, and in contrast to previous work on similar devices, deviations from the main Gaussian lobe up to 25 microns from the focus and down to the 5 × 10−6 level in relative intensity are characterized as well; we show that along one dimension the intensity of these weak sidelobes approaches the limit imposed by diffraction from the finite field extent in the grating region. Additionally, we characterize the polarization purity in the focal region, observing at the center of the focus a low impurity <3 × 10−4 in relative intensity. Our approach allows quick, intuitive design of devices with such performance, which may be applied in trapped-ion quantum information processing and generally in any systems requiring optical routing to or from objects 10 s–100 s of microns from a chip surface, but benefitting from the parallelism and density of planar-fabricated dielectric integrated optics.
format article
author Karan K. Mehta
Rajeev J. Ram
author_facet Karan K. Mehta
Rajeev J. Ram
author_sort Karan K. Mehta
title Precise and diffraction-limited waveguide-to-free-space focusing gratings
title_short Precise and diffraction-limited waveguide-to-free-space focusing gratings
title_full Precise and diffraction-limited waveguide-to-free-space focusing gratings
title_fullStr Precise and diffraction-limited waveguide-to-free-space focusing gratings
title_full_unstemmed Precise and diffraction-limited waveguide-to-free-space focusing gratings
title_sort precise and diffraction-limited waveguide-to-free-space focusing gratings
publisher Nature Portfolio
publishDate 2017
url https://doaj.org/article/203fc8a317a24223afdb09cdf9a0f811
work_keys_str_mv AT karankmehta preciseanddiffractionlimitedwaveguidetofreespacefocusinggratings
AT rajeevjram preciseanddiffractionlimitedwaveguidetofreespacefocusinggratings
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