Precise and diffraction-limited waveguide-to-free-space focusing gratings
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. Wi...
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| Format: | Article |
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Springer Nature
2018
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| Online Access: | http://hdl.handle.net/1721.1/113592 https://orcid.org/0000-0002-0917-7182 https://orcid.org/0000-0003-0420-2235 |
| _version_ | 1826196846009122816 |
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| author | Mehta, Karan K. Ram, Rajeev J. Mehta, Karan Kartik Ram, Rajeev J |
| author2 | Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science |
| author_facet | Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science Mehta, Karan K. Ram, Rajeev J. Mehta, Karan Kartik Ram, Rajeev J |
| author_sort | Mehta, Karan K. |
| collection | MIT |
| description | 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[superscript -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[superscript -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. |
| first_indexed | 2024-09-23T10:38:54Z |
| format | Article |
| id | mit-1721.1/113592 |
| institution | Massachusetts Institute of Technology |
| last_indexed | 2024-09-23T10:38:54Z |
| publishDate | 2018 |
| publisher | Springer Nature |
| record_format | dspace |
| spelling | mit-1721.1/1135922022-09-27T13:57:50Z Precise and diffraction-limited waveguide-to-free-space focusing gratings Mehta, Karan K. Ram, Rajeev J. Mehta, Karan Kartik Ram, Rajeev J Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science Mehta, Karan Kartik Ram, Rajeev J 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[superscript -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[superscript -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. National Science Foundation (U.S.) (Program ECCS-1408495) 2018-02-12T19:21:35Z 2018-02-12T19:21:35Z 2017-05 2017-01 2018-02-09T17:45:37Z Article http://purl.org/eprint/type/JournalArticle 2045-2322 http://hdl.handle.net/1721.1/113592 Mehta, Karan K., and Rajeev J. Ram. “Precise and Diffraction-Limited Waveguide-to-Free-Space Focusing Gratings.” Scientific Reports, vol. 7, no. 1, Dec. 2017. https://orcid.org/0000-0002-0917-7182 https://orcid.org/0000-0003-0420-2235 http://dx.doi.org/10.1038/S41598-017-02169-2 Scientific Reports Creative Commons Attribution 4.0 International License https://creativecommons.org/licenses/by/4.0/ application/pdf Springer Nature |
| spellingShingle | Mehta, Karan K. Ram, Rajeev J. Mehta, Karan Kartik Ram, Rajeev J Precise and diffraction-limited waveguide-to-free-space focusing gratings |
| title | 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_short | Precise and diffraction-limited waveguide-to-free-space focusing gratings |
| title_sort | precise and diffraction limited waveguide to free space focusing gratings |
| url | http://hdl.handle.net/1721.1/113592 https://orcid.org/0000-0002-0917-7182 https://orcid.org/0000-0003-0420-2235 |
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