Femtosecond laser modulated into Bessel beam by spatial light modulator for Fresnel zone plate processing

• A femtosecond laser Bessel beam modulated by an SLM enables fabrication of micro-Fresnel zone plates with dramatically reduced processing time. • Processing time for a 60 μm FZP on GaAs is cut from 30 min to 1.5 min, a 20-fold improvement in efficiency. • The adverse central ablation hole caused by Bessel modulation is eliminated by superimposing blazed grating holograms. • SLM-machined FZPs exhibit superior morphology and higher diffraction efficiency, supporting applications in computed tomography and solar photovoltaic cells.