Towards nanofabrication with UV femtosecond fiber laser

H. Huang, L-M. Yang, J. Liu
PolarOnyx, Inc., US

Keywords: fiber laser, femtosecond laser, UV laser, nanofabrication, direct writing, ablation threshold


In this paper, a UV fs fiber laser was used for direct writing nanofabrication on different materials. The laser used is a commercialized mode-locked fiber laser (PolarOnyx Uranus Series), generating typically Gaussian shape pulses (750 fs, 1 µm & 1 MHz). The maximum output pulse energy is 10 μJ and the fourth harmonic generation (FHG, 258 nm) was generated and used for the experiment. It is found that the size of direct written features depends strongly upon pulse energy, as well as the relative position of the laser focal spot with respect to the material surface. The smallest line widths were found to be less than 100 nm for both glass and polymer materials. By reducing the pulse energy to a value slightly above the threshold at which features vanish, we can consistently write line features with sub wavelength width. Furthermore, ripples in good order with 100 nm period and grooves with about 50 nm width and 50 nm depth were found. This fs UV fiber laser based technique is inherently simple, direct, highly-reproducible and material independent. This enabling technology has potentially broad applications for MEMS construction, ultra-high-density microelectronics, nanofluidics, materials science, optical memory, and biological science.