1. Multi-photon Direct Laser Writing of Curved Waveguides in SU-8
for Beam Bending
Elizabeth L. Isaaca, Rashi Sharmab, Stephen M. Kueblerb,c
Summary and Future Work
Acknowledgements
References
aDepartment of Chemistry Otterbein University Westerville, OH 32081, USA , bDepartment of Chemistry, cCREOL, The College of Optics and Photonics University of Central Florida,
Orlando, FL 32816, USA
Results and DiscussionIntroduction
• A waveguide is a structure that guides waves/beams
such as light around tight corners. We fabricated
curved waveguides using SU-8 resin.
• Multiphoton direct laser writing (mp-DLW) exploits
multi-photon absorption and is used to create nano
and micro structures in photosensitive materials1.
• Spatially variant photonic crystals (SVPCs) are
lattice-like microstructures which can guide light
efficiently through tight corners2. In this project,
curved waveguides were fabricated to compare the
light guiding efficiency of SVPCs with respect to the
waveguides.
• This project helped improve the design and process
for waveguide fabrication.
Fig 1. The polymerization reaction of SU-8 as it cross-
links in response to laser excitation.
Fig 5. (A) is a Cube3D Viewer image of what the waveguide is
expected to look like. The image was generated by code in a text
file. (B) is a scanning electron microscope (SEM) image of a
curved waveguide fabricated on top of a support pillar (100 µm).
The web-like material next to the waveguide may be un-
polymerized SU-8 that was not entirely washed away by the
PGMEA. The waveguide is slightly distorted near the bottom
right. More work is need to be done to discover why this
deformation occurred.
• The curved waveguides were fabricated successfully in SU-8
photoresist using mp-DLW.
• The fabricated waveguides were imaged with SEM.
• In future work the light guiding efficiency of the waveguides
will be characterized using a 2.94 µm laser source.
I’d like to thank Dr. Kuebler, my graduate mentor Rashi Sharma,
and the UCF College of Graduate Studies for this opportunity.
1. M.T. Gale, M. Rossi, J. Pedersen, H. Shuetz“Fabrication of continuous-relief
micro-optical elements by direct laser writing in photoresists”Opt. Eng.
33(11), 3556-3566 (Nov 01, 1994). doi:10.1117/12.179892
2. J. L. Digaum, J. J. Pazos, J. Chiles, J. D'Archangel, G. Padilla, A. Tatulian,
R. C. Rumpf, S. Fathpour, G. D. Boreman, and S. M.Kuebler
"Tight Control of Light Beams in Photonic Crystals with Spatially-Variant
Lattice Orientation“ Optics Express, vol. 22, pp. 25788-25804, October 2014.
Experimental Method
a. Sample Preparation
Fig 2. SU-8 was dropped on a glass slide and spincoated to
form a thin layer. The sample was baked to remove excess
solvent.
b. Fabrication
Fig 3. A Ti:Sapphire laser was used to photo-pattern the
microstructures using mp-DLW.
c. Sample Development
Fig 4. The sample was rinsed with PGMEA to remove un-
polymerized SU-8 and left behind a free standing structure.
Photogenerated H+
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