Abstract
An ethoxylated bis-phenol-A dimethacrylate based photoresin BPE-100 of relatively high photosensitivity and modulus is used for the creation of sub-50 nm features. This is achieved by using the direct laser writing technique based on the single-photon photoinhibited polymerization. The super-resolution feature is realized by overlapping two laser beams of different wavelengths to enable the wavelength-controlled activation of photoinitiating and photoinhibiting processes in the polymerization. The increased photosensitivity of the photoresin promotes a fast curing speed and enhances the photopolymerization efficiency. Using the photoresin BPE-100, we achieve 40 nm dots for the first time in the super-resolution fabrication technique based on the photoinhibited polymerization, and a minimum linewidth of 130 nm. The influence of the power of the inhibiting laser and the exposure time on the feature size is studied and the results agree well with the prediction obtained from a simulation based on a non-steady-state kinetic model.
Highlights
In the past decade, the direct laser writing technique employing photo-initiated polymerization has attracted enormous research interests due to its broad applications in microfluidic devices, microelectromechanics systems, photonics and optical information storage and processing [1,2,3,4,5,6]
Fabrication resolution limited by the diffraction nature of light in the direct laser writing technique represents a great challenge for achieving functional structures and devices, such as metamaterials and photonic crystals operating in the visible wavelength region
We demonstrate that a methacrylate-based monomer can be used to increase the fabrication speed and reduce the feature size in the fabrication based on the single-photon photoinhibited polymerization process
Summary
The direct laser writing technique employing photo-initiated polymerization has attracted enormous research interests due to its broad applications in microfluidic devices, microelectromechanics systems, photonics and optical information storage and processing [1,2,3,4,5,6]. As the exposure zone of the inhibiting beam was modulated to a doughnut shape, a diffraction-limit-free polymerization volume could be generated in the centre of the exposed region This approach neatly combined the production of a smaller photo-active voxel and the prevention of dark polymerization [8], which is of great promise to realize super-resolution fabrication. For a given light absorber—a initiator or a photosensitizer and a polymerizable group, an increase of the photosensitivity of the photoresin, where the photosensitivity can be expressed as the amount of photoenergy that is required to react half of the monomers, can enhance the quantum yield of the photoinduction and photopolymerization triggered by the photons absorbed In this regard, the population of photons required to achieve the polymerization threshold is decreased, which potentially leads to a reduced light scattering. The minimum feature size is reduced to 40 nm by the irradiation of inhibition light, which is 1/12 of the wavelength of the initiating laser used in the fabrication
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
