Diffusion-assisted high-resolution direct femtosecond laser writing.
We present a new method for increasing the resolution of direct femtosecond laser writing by multiphoton polymerization, based on quencher diffusion. This method relies on the combination of a mobile quenching molecule with a slow laser scanning speed, allowing the diffusion of the quencher in the scanned area and the depletion of the multiphoton-generated radicals. The material we use is an organic-inorganic hybrid, while the quencher is a photopolymerizable amine-based monomer which is bound on the polymer backbone upon fabrication of the structures. We use this method to fabricate woodpile structures with a 400 nm intralayer period. This is comparable to the results produced by direct laser writing based on stimulated-emission-depletion microscopy, the method considered today as state-of-the-art in 3D structure fabrication. We optically characterize these woodpiles to show that they exhibit well-ordered diffraction patterns and stopgaps down to near-infrared wavelengths. Finally, we model the quencher diffusion, and we show that radical inhibition is responsible for the increased resolution.
IESL-FORTH , N. Plastira 100, 70013, Heraklion, Crete, Greece.
Ioanna
I
Sakellari
Elmina
E
Kabouraki
David
D
Gray
Vytautas
V
Purlys
Costas
C
Fotakis
Alexander
A
Pikulin
Nikita
N
Bityurin
Maria
M
Vamvakaki
Maria
M
Farsari
D000588:Amines / Q000737:chemistry; D004058:Diffusion; D005021:Ethylamines / Q000737:chemistry; D007834:Lasers; D008689:Methacrylates / Q000737:chemistry; D055620:Optical Phenomena; D017785:Photons; D058105:Polymerization; D011327:Printing / Q000379:methods*; D013997:Time Factors
C510335:2-dimethylaminoethyl methacrylate; D000588:Amines; D005021:Ethylamines; D008689:Methacrylates