Structuring optical vortices in 3D

November 18, 2021

Optical vortices —light structures which look like donuts and can rotate around their axis of propagation— have attracted wide interest as new means for free space communications, optical trapping, and structured illumination in microscopes. Current wavefront shaping methods, however, can only provide limited control over the vorticity and the polarization (photon’s spin) of those beams in 3D space, thus limiting their application. In this study, we introduce a new type of metasurfaces which can generate complex optical vortices in which both the vortex strength and polarization state...

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Metasurface pulse compressor

Silicon nanocoatings make ultrafast pulses ultrafaster

November 12, 2021

Transparent bulk optical components have an unfortunate tendency to stretch out ultrashort laser pulses upon transmission. This effect – also known as group delay dispersion – destroys the carefully designed time-structure of the affected pulses. In this study, we show that precisely shaped silicon nanopillars can achieve the opposite effect, compressing the laser pulses and compensating for the dispersion of other optical elements. The technology is ready to be coated onto abundantly available standard optics to allow their application in the future of ultrafaster femtosecond optics....

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