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Formation of micro-optical structures by self-writing processes in photosensitive polymers
Ulrich Streppel1, Peter Dannberg, Christoph Wächter
1Fraunhofer Institut für Angewandte Optik und Feinmechanik, Winzerlaer Strasse 10, 07745 Jena, Germany. ulrich.streppel@iof.fraunhofer.de
Applied Optics
|July 2, 2003
Summary
Local UV exposure cures polymers, causing nonlinear refractive index changes and filamentation. Controlling material and exposure parameters enables steered, self-written micro-optical structure formation.
Area of Science:
- Polymer Science
- Optical Engineering
- Materials Science
Background:
- UV-sensitive polymers undergo local curing upon exposure.
- This curing involves a saturable, irreversible nonlinear change in refractive index.
- This nonlinear effect leads to filamentation within the hardening polymer.
Purpose of the Study:
- Investigate the physical mechanisms behind UV-induced polymer curing and filamentation.
- Analyze how influencing factors can steer the self-written formation of micro-optical structures.
- Explore controlled structure formation through material and exposure parameter manipulation.
Main Methods:
- Simulated structure formation using an iterative beam propagation method.
- Considered process parameters include photoinitiator concentration and exposure intensity.
- Experimental validation using a beam shaper in a UV contact exposure process.
Main Results:
- Demonstrated theoretically and experimentally that parameter variation controls structure formation.
- Showcased opportunities for controlled micro-optical structure fabrication.
- Successfully prepared high-aspect-ratio conic structures.
Conclusions:
- Material and exposure parameters are critical for controlled micro-optical structure formation in UV-sensitive polymers.
- The study provides a foundation for steered, partly self-written fabrication of micro-optical devices.
- The presented experimental configuration is effective for creating complex microstructures.