Interference lithography for the synthesis of three-dimensional lattices in SU-8: Interrelation between porosity, an exposure dose and a grating period

•Three dimensional gratings with different periods were synthesized in SU-8.•The best exposure time is different for making of gratings with different periods.•To obtain porous gratings with smaller periods smaller exposure doses are requires.•The suitable range of exposure doses is much narrower for smaller periods.

Three-dimensional gratings with different periods were synthesized in SU-8 photoresist through its triple exposure to two-wave interference pattern. Interrelation between porosity, an exposure dose and a grating period were investigated. It was found that decreasing porous grating periods require decreasing density of absorbed laser radiation. Moreover, decrease of grating periods leads to a narrow range of radiation dose that allows us to obtain porous structure.