Figure 5
From: Ultrafast laser processing of materials: from science to industry
Optical vortex generating spiral waveplates. Smaller (a, b) and larger (c) cross-sections optical vortex generators. (a, b) SEM images of micro-plates made by point-by-point exposure (inset in b shows 3D construction of irradiation matrix). (c) Height scans at four locations of the step edge of the spiral plate; diameter of the plate was 60 μm. Reproduced with permission from Ref. 59. Copyright (2010), AIP Publishing LLC.
