Femtosecond laser nanostructuring in porous glass with sub-50 nm feature sizes

Abstract

We report on controllable production of nanostructures embedded in a porous glass substrate by femtosecond laser direct writing. We show that a hollow nano-void with a lateral size of ~40 nm and an axial size of ~1500 nm can be achieved by manipulating the peak intensity and polarization of the writing laser beam. Our finding enables direct construction of 3D nanofluidics inside glass.

Femtosecond laser direct writing of three-dimensional micro/nanofluidics in porous glass

“…Here, we achieve fabrication resolutions far beyond diffraction limit (i. e., ~40 nm) by combining the threshold effect and the exotic phenomenon of formation of periodic nanograting during the process of laser writing in the porous glass immersed in water. In the porous glass, we observe that the nanogratinglike structures induced by femtosecond laser irradiation constitute an array of hollow cracks with a width down to ~40 nm [6]. When the femtosecond laser intensity is intentionally reduced to a level at which only the hollow nanocrack produced in the central area of the focal volume can survive, a single-line nanofluidic channel is produced, as shown in Fig.…”

“…2(a) and 2(b). Control of the diameter of the nanochannel is achieved by adjusting the pulse energy of the writing beam [6]. Here, we achieve fabrication resolutions far beyond diffraction limit (i. e., ~40 nm) by combining the threshold effect and the exotic phenomenon of formation of periodic nanograting during the process of laser writing in the porous glass immersed in water.…”

“…This 3D fabrication capability further opens up new avenues for fabricating a variety of integrated optofluidic microchips for chemical sensing and biological analysis. In this contribution, we focus on fabrication of micro-/nanofluidic structures with nearly arbitrary 3D geometries and configurations in porous glass [3][4][5][6]. Fabrication of long 3D microfluidic channels with almost arbitrary lengths and configurations can be achieved by water-assisted femtosecond laser direct writing inside a porous glass.…”

Progress in ultrafast laser processing and future prospects

“…Further reduction to a level very near to the ablation threshold results in only a single cycle of the modulated energy distribution in the central area of the focal volume ( Fig. 7(c)), which creates a single line nanogroove [53][54][55][56]. Using this scheme, an array of single nanogrooves with widths less than 40 nm were fabricated on ZnO, as shown in the SEM image of Fig.…”

Self-organized voids revisited: Experimental verification of the formation mechanism

“…Moreover, self-assembled polarization-dependent nanogratings induced inside porous glass have recently been reported to be reduced to a single sub-50nm-wide nanochannel by the near-threshold-ablation technique, and this kind of single nanochannel has further been employed as building blocks of a 3D micro-nanofluidic device which has been used to demonstrate DNA analysis. [12][13] These research progress opens new opportunities of self-assembled nanostructures in 3D micro-nanofluidic application.…”