Submicrometer 3D structures fabrication enabled by one-photon absorption direct laser writing
Résumé
We demonstrate a new 3D fabrication method to achieve the
same results as those obtained by the two-photon excitation technique, by
using a simple one-photon elaboration method in a very low absorption
regime. Desirable 2D and 3D submicrometric structures, such as spiral,
chiral, and woodpile architectures, with feature size as small as 190 nm
have been fabricated, by using just a few milliwatts of a continuous-wave
laser at 532 nm and a commercial SU8 photoresist. Different aspects of
the direct laser writing based on ultralow one-photon absorption (LOPA)
technique are investigated and compared with the TPA technique, showing
several advantages, such as simplicity and low cost.