Maskless laser nano-lithography of glass through sequential activation of multi-threshold ablation

Abstract

Controllable nanofabrication is at the very foundation of nano-science and nano-technology. Today, ultrafast laser writing has been broadly adopted for micro-fabrication because of its ability to make precise and rapid processing of almost all types of materials in an ambient environment. However, direct laser writing is typically unsuitable for high-quality 2D nano-patterning. In this work, we introduce a maskless laser nano-lithographic technique that allows us to create regular 2D periodic nanopatterns on glass. Glass is a particularly challenging material since it does not absorb light readily. Our strategy starts with a glass sample being coated with a thin layer of metal, and then irradiated with a series of pulse bursts at progressively increasing fluence levels. This process allows us to sequentially activate a series of tailored physical processes that lead to the formation of regular 2D periodic nanopatterns on glass. The formation mechanism of this nano-patterning is also simulated numerically and further corroborated by a series of control experiments. We also show controllability in forming various shapes and sizes of nanopatterns through tailored fluence doses. Our technique provides a high-speed and low-cost method for glass nanofabrication.

Quo Vadis LIPSS?—Recent and Future Trends on Laser-Induced Periodic Surface Structures

“…Apart from the strategy to reduce the nonlinearity via the irradiation wavelength [ 82 ], another way to overcome this difficulty can lie in adding a very thin strongly-absorbing surface overlayer on the dielectric in order to facilitate resonant coupling effects of the laser radiation to the material underneath. For hexagonally arranged ablative nanobumps on glass, tens of nanometer thick copper and silver coatings were shown to be suitable [ 83 , 84 ]. Later, Kunz et al demonstrated that large surface areas homogeneously covered by HSFL can be processed on fused silica by the help of an additional 20 nm-thick gold layer [ 85 ].…”

Femtosecond laser‐produced optical absorbers for solar‐thermal energy harvesting

“…On the other hand, femtosecond (fs) laser processing is a single-step, scalable, and simple technique that can directly transform a surface to become a selective or broadband optical absorber, and the technology can be applied to a range of materials including metals, 29,30 semiconductors, 31,32 dielectrics, 33,34 glass, 35 polymer, 36,37 and even on biological materials. [38][39][40] Unlike cermet and other absorber coatings that are fabricated using additive coating technologies, fs-laser processing is a subtractive approach that creates hierarchical micro/nano-scaled patterns directly on the substrate without adding any weight, hazard, or complexity.…”

Spectral absorption control of femtosecond laser-treated metals and application in solar-thermal devices

“…Of interest, one-dimensional (1D) femtosecond laser-induced periodic surface structures (fs-LIPSSs) with subwavelength periodicity that can be realised on a wide range of materials have attracted considerable attention 1,2 . Different techniques have been employed to address the spatial uniformity of fs-LIPSSs, for instance, positive and negative feedback mechanisms on titanium substrates 9 , chemicalassisted fs-laser-treatment 10 , high-uniformity fs-LIPSSs creation via temporally delayed multi-pulse irradiation 11,12 , non-ablative fs-laser structuring technique 13 , or self-organisation from metal-assisted pattern formation on glass 14 . While these studies showed the ability to produce more regular surface features, they did not demonstrate the ability to design the surface properties, which is crucial at the device engineering and application level.…”