Exceeding the diffraction limit with single-photon photopolymerization and photo-induced termination

Benjamin A. Kowalski, Timothy F. Scott, Christopher N. Bowman, Amy C. Sullivan, Robert R. McLeod

Research output: Chapter in Book/Report/Conference proceedingConference PaperOther

3 Citations (Scopus)

Abstract

The fabrication of 3D microstructures has been realized by numerous researchers using two-photon polymerization. The premise of these studies is that the confinement provided by localized, two-photon absorption results in polymerization only near the focal point of the focused write beam and unwanted polymerization due to superposition of the out-offocus exposures is significantly reduced, enabling the fabrication of complex structures with features below the diffraction limit. However, the low cross-section of two-photon absorbers typically requires excitation by pulsed Ti:Sapphire laser at 800 nm, resulting in polymerized features that are actually larger than those created by one-photon absorption at half the wavelength. Here we describe a single photon photolithographic technique capable of producing features not limited by the physics of diffraction by utilizing a resin which is able to be simultaneously photoinitiated using one wavelength of light and photoinhibited using a second wavelength. Appropriate overlapping of these two wavelengths produces feature sizes smaller than the diffraction limit and reduces polymerization in the out-of-focus regions while avoiding the high light intensities demanded by multi-photon initiation. Additionally, because the photoinhibiting species are non-propagating radicals which recombine when the irradiation is ceased, memory effects typical of photochromic initiators are avoided, allowing rapid and arbitrary patterning.

Original languageEnglish
Title of host publicationOrganic 3D Photonics Materials and Devices II
DOIs
Publication statusPublished - 12 Nov 2008
Externally publishedYes
EventOrganic 3D Photonics Materials and Devices II - San Diego, CA, United States of America
Duration: 12 Aug 200812 Aug 2008

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume7053
ISSN (Print)0277-786X

Conference

ConferenceOrganic 3D Photonics Materials and Devices II
CountryUnited States of America
CitySan Diego, CA
Period12/08/0812/08/08

Keywords

  • Lithography
  • Photochromic polymers
  • Two photon polymerization

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