Single femtosecond pulse nanochannel formation in glass

Single pulse femtosecond laser damage in transparent dielectrics has been shown to occur through nonlinear damage mechanisms that can allow material removal on scales well below the classical limit of the order of the wavelength of the incident light. These mechanisms can be harnessed to allow the optical machining of devices on the nanoscale. We observe the formation of high aspect-ratio nanochannels by single femtosecond pulses. These channels, several microns in length, can be formed at the front or rear surface of a sample, corresponding to conditions under which spherical aberration is expected and where it is minimized. The presence of similar channels at both locations suggests that aberration does not play a critical role in nanochannel creation, and we present evidence supporting a dominant role of self focusing and microscale filamentation. Applications for these long nanoscale diameter channels include nanopores, nanowells, or out-of-plane vias. The ability to generate these channels with single pulses allows rapid fabrication that complements existing techniques, thus addressing a major limitation to fabrication of microfluidics and nanopores.