Nanoscale energy deposition in glass by double ultrashort Gauss-Bessel pulses

International audienceThe main advantage of ultrafast laser-based processing techniques is the capability of structuring the material in three dimensions, even inside the bulk of transparent materials. It allows for a very precise control and versatility of the manufacturing process. The formation of high aspect ratio voids in glass with diameters in the hundreds of nanometres range using only a single ultrafast laser pulse is particularly useful for many applications. Drilling of high aspect ratio nanochannels has been particularly successful when using zeroth-order Bessel beams [1, 2]. However, depending on the material and illumination geometry, limitations arise on the maximal and minimal nanochannel diameter (Fig. 1a). Here, we demonstrate that double pulses drastically improve the efficiency of the drilling (Fig. 1b) and absorption measurement allow for deciphering the mechanism