We report on fabrication of periodic arrays of polyethylene glycol diacrylate (PEG-DA), a biocompatible hydrogel,
useful in biomedical applications. The structures were produced by means of multi beam laser interference lithography
with both nanosecond (266 and 355 nm of wavelengths with pulses lasting 10 ns) and femtosecond pulsed lasers (800
nm of wavelength and 90 fs laser pulses). Configurations involving two, four and five laser beams were utilized
obtaining a wide variety of patterns with different feature sizes in the micrometer scale. Through this technique, we
demonstrated the ability to fabricate high feature density patterns over large areas without the use of templates or masks.
In addition, resolution and geometrical characteristic of the periodic arrays are discussed as function of pulse duration
and laser processing parameters. The photopolymerization nature of the process was also investigated.