Tomographic refractive index profiling of direct laser written waveguides
The fabrication of complex integrated photonic devices via direct laser writing is a powerful and rapidly developing technology. However, the approach is still facing several challenges. One of them is the reliable quantitative characterization of refractive index (RI) changes induced upon laser exp...
| Main Authors: | , , , , , , , |
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| Format: | Journal article |
| Sprog: | English |
| Udgivet: |
The Optical Society
2021
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| _version_ | 1826261582269644800 |
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| author | Barré, N Shivaraman, R Ackermann, L Moser, S Schmidt, M Salter, P Booth, M Jesacher, A |
| author_facet | Barré, N Shivaraman, R Ackermann, L Moser, S Schmidt, M Salter, P Booth, M Jesacher, A |
| author_sort | Barré, N |
| collection | OXFORD |
| description | The fabrication of complex integrated photonic devices via direct laser writing is a powerful and rapidly developing technology. However, the approach is still facing several challenges. One of them is the reliable quantitative characterization of refractive index (RI) changes induced upon laser exposure. To this end, we develop a tomographic reconstruction algorithm following a modern optimization approach, relying on accelerated proximal gradient descent, based on intensity images only. Very recently, such algorithms have become the state of the art in the community of bioimaging, but have never been applied to direct laser written structures such as waveguides. We adapt the algorithm to our concern of characterizing these translation-invariant structures and extend it in order to jointly estimate the aberrations introduced by the imaging system. We show that a correct estimation of these aberrations is necessary to make use of data recorded at larger angles and that it can increase the fidelity of the reconstructed RI profiles. Moreover, we present a method allowing to cross-validate the RI reconstructions by comparing en-face widefield images of thin waveguide sections with matching simulations based on the retrieved RI profile.
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| first_indexed | 2024-03-06T19:23:38Z |
| format | Journal article |
| id | oxford-uuid:1af610e5-a6c1-4fb1-b483-4bfa87e17e30 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-06T19:23:38Z |
| publishDate | 2021 |
| publisher | The Optical Society |
| record_format | dspace |
| spelling | oxford-uuid:1af610e5-a6c1-4fb1-b483-4bfa87e17e302022-03-26T10:57:42ZTomographic refractive index profiling of direct laser written waveguidesJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:1af610e5-a6c1-4fb1-b483-4bfa87e17e30EnglishSymplectic ElementsThe Optical Society2021Barré, NShivaraman, RAckermann, LMoser, SSchmidt, MSalter, PBooth, MJesacher, AThe fabrication of complex integrated photonic devices via direct laser writing is a powerful and rapidly developing technology. However, the approach is still facing several challenges. One of them is the reliable quantitative characterization of refractive index (RI) changes induced upon laser exposure. To this end, we develop a tomographic reconstruction algorithm following a modern optimization approach, relying on accelerated proximal gradient descent, based on intensity images only. Very recently, such algorithms have become the state of the art in the community of bioimaging, but have never been applied to direct laser written structures such as waveguides. We adapt the algorithm to our concern of characterizing these translation-invariant structures and extend it in order to jointly estimate the aberrations introduced by the imaging system. We show that a correct estimation of these aberrations is necessary to make use of data recorded at larger angles and that it can increase the fidelity of the reconstructed RI profiles. Moreover, we present a method allowing to cross-validate the RI reconstructions by comparing en-face widefield images of thin waveguide sections with matching simulations based on the retrieved RI profile. |
| spellingShingle | Barré, N Shivaraman, R Ackermann, L Moser, S Schmidt, M Salter, P Booth, M Jesacher, A Tomographic refractive index profiling of direct laser written waveguides |
| title | Tomographic refractive index profiling of direct laser written waveguides |
| title_full | Tomographic refractive index profiling of direct laser written waveguides |
| title_fullStr | Tomographic refractive index profiling of direct laser written waveguides |
| title_full_unstemmed | Tomographic refractive index profiling of direct laser written waveguides |
| title_short | Tomographic refractive index profiling of direct laser written waveguides |
| title_sort | tomographic refractive index profiling of direct laser written waveguides |
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