Title: Enabling High Precision Gradient Index Control in Subsurface Multiphoton Lithography

Abstract

Multiphoton lithography inside a mesoporous host can create optical components with continuously tunable refractive indices in three-dimensional (3D) space. However, the process is very sensitive at exposure doses near the photoresist threshold, leading previous work to reliably achieve only a fraction of the available refractive index range for a given material system. Here, we present a method for greatly enhancing the uniformity of the subsurface micro-optics, increasing the reliable index range from 0.12 (in prior work) to 0.37 and decreasing the standard deviation (SD) at threshold from 0.13 to 0.0021. Three modifications to the previous method enable higher uniformity in all three spatial dimensions: (1) calibrating the planar write field of mirror galvanometers using a spatially varying optical transmission function which corrects for large-scale optical aberrations; (2) periodically relocating the piezoelectrically driven stage, termed piezo-galvo dithering, to reduce small-scale errors in writing; and (3) enforcing a constant time between each lateral cross section to reduce variation across all writing depths. With this new method, accurate fabrication of optics of any index between n = 1.20 and 1.57 (SD < 0.012 across the full range) was achieved inside a volume of porous silica. We demonstrate the importance of this increased accuracymore » and precision by fabricating and characterizing calibrated two-dimensional (2D) line gratings and flat gradient index lenses with significantly better performance than the corresponding control devices. As a visual representation, the University of Illinois logo made with 2D line gratings shows significant improvement in its color uniformity across its width.« less

Authors:

Littlefield, Alexander J.  ^[1];

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• Search DOE PAGES for ORCID "0000-0003-2348-9032"

Xie, Dajie  ^[2];

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• Search DOE PAGES for ORCID "0000-0002-4792-3457"

Richards, Corey A.  ^[2];

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• Search DOE PAGES for ORCID "0000-0001-7495-4083"

Ocier, Christian R. ^[2]; Gao, Haibo  ^[2];

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Messinger, Jonah F.  ^[3];

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• Search DOE PAGES for ORCID "0000-0003-0775-7180"

Ju, Lawrence ^[1]; Gao, Jingxing  ^[1];

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• Search DOE PAGES for ORCID "0009-0000-2963-3731"

Edwards, Lonna ^[1]; Braun, Paul V.  ^[4];

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• Search DOE PAGES for ORCID "0000-0003-4079-8160"

Goddard, Lynford L.  ^[5]

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• Search DOE PAGES for ORCID "0000-0002-0737-1205"

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1. Department of Electrical and Computer Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States, Nick Holonyak, Jr., Micro and Nanotechnology Laboratory, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
2. Department of Materials Science and Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States, Materials Research Laboratory, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States, Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
3. Materials Research Laboratory, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States, Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States, Department of Physics, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
4. Nick Holonyak, Jr., Micro and Nanotechnology Laboratory, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States, Department of Materials Science and Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States, Materials Research Laboratory, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States, Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States, Department of Mechanical Science and Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
5. Department of Electrical and Computer Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States, Nick Holonyak, Jr., Micro and Nanotechnology Laboratory, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States, Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States

Publication Date:

Wed Mar 29 00:00:00 EDT 2023

Research Org.:

Univ. of Illinois at Urbana-Champaign, IL (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES); National Science Foundation (NSF)

OSTI Identifier:

1963961

Alternate Identifier(s):

OSTI ID: 2001042

Grant/Contract Number:  

SC0019140; ECCS-1935289

Resource Type:

Published Article

Journal Name:

ACS Photonics

Additional Journal Information:

Journal Name: ACS Photonics Journal Volume: 10 Journal Issue: 9; Journal ID: ISSN 2330-4022

Publisher:

American Chemical Society

Country of Publication:

United States

Language:

English

Subject:

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 3D direct laser writing; multiphoton microscopy; graded index lens; high contrast gratings; porous silicon; calibration; fluorescence; lasers; optical properties; power