title: Rapid bespoke laser ablation of variable period grating structures using a digital micromirror device for multi-colored surface images.
abstract: A digital micromirror device has been used to project variable-period grating patterns at high values of demagnification for direct laser ablation on planar surfaces. Femtosecond laser pulses of ∼1  mJ pulse energy at 800 nm wavelength from a Ti:sapphire laser were used to machine complex patterns with areas of up to ∼1  cm2on thin films of bismuth telluride by dynamically modifying the grating period as the sample was translated beneath the imaged laser pulses. Individual ∼30 by 30 μm gratings were stitched together to form contiguous structures, which had diffractive effects clearly visible to the naked eye. This technique may have applications in marking, coding, and security features.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Heath
authors.forename: Ben
authors.initials: B
authors.lastname: Mills
authors.forename: Matthias
authors.initials: M
authors.lastname: Feinaeugle
authors.forename: Robert W
authors.initials: RW
authors.lastname: Eason