Fig. 5: Writing, erasing and rewriting inside silicon.
From: In-chip critical plasma seeds for laser writing of reconfigurable silicon photonics systems
a Written voxels (infrared microscopy, lateral view) before (first row) and after (second row) thermal treatments using a furnace (>1000 °C for 4 h). The comparison reveals a superior erasing capacity when modifications are produced with the seeded writing approach (double pulse). b Similar voxels produced by the two writing methods (top view observations) before and after subsequent irradiation using a focused nanosecond laser (0.3µJ 5-ns 1550-nm pulses). Similar conclusions can be stressed with this scheme giving a solution for local erasure. c Three QR codes subsequently produced at the same location inside a silicon wafer (300-µm depth) by applying seeded writing, nanosecond laser erasing and seeded re-writing procedures. d Scattering images of a voxel repeatedly written and erased for more than 100 cycles with optimized double-pulse and nanosecond laser conditions. The graph represents the integrated scattering signal from the darkfield microcopy images acquired after each irradiation (examples shown on top). Scale bars are 20 µm.
