Multi-sector broadband diffractive optical elements (DOEs) were designed and fabricated from fused silica for high-efficiency multiplexing of femtosecond and nanosecond Gaussian laser beams into multiple (up to one 100) optically tunable microbeams with increased high-numerical aperture (NA) focal depths. Various DOE-related issues, such as high-NA laser focusing, laser pulsewidth, and DOE symmetry-dependent heat conduction effects, as well as the corresponding spatial resolution, were discussed in the context of high-throughput laser patterning. The increased focal depths provided by such DOEs, their high multiplexing efficiency and damage threshold, as well as easy-to-implement optical shaping of output microbeams provide advanced opportunities for direct, mask-free, and vacuum-free high-throughput subtractive (ablative) and displacive pulsed-laser patterning of various nanoplasmonic films for surface-enhanced spectroscopy, sensing, and light control.

Ultrafast intense photoexcitation of a silicon surface is complementarily studied experimentally and theoretically, with its prompt optical dielectric function obtained by means of time-resolved...

Unusually high densification ⩽26% was obtained without lateral residual stresses within the laser beam waist inside porous glass during its multi-shot femtosecond laser irradiation, which may induce in the glass the related high refractive index change ~0.1. Corresponding laser irradiation regimes, resulting in such ultra-densification, decompaction and voids inside the glass, were revealed as a function of laser pulse energy and scanning rate, and were discussed in terms of thermal and hydrodynamic processes in the silica network.