English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We report on efficient nonlinear generation of ultrafast, higher order"perfect" vortices at the green wavelength. Based on Fourier transformation ofthe higher order Bessel-Gauss beam generated through the combination of spiralphase plate and axicon we have transformed the Gaussian beam of the ultrafastYb-fiber laser at 1060 nm into perfect vortices of power 4.4 W and order up to6. Using single-pass second harmonic generation (SHG) of such vortices in 5-mmlong chirped MgO-doped, periodically poled congruent LiNbO$_3$ crystal we havegenerated perfect vortices at green wavelength with output power of 1.2 W andvortex order up to 12 at single-pass conversion efficiency of 27% independentof its order. This is the highest single-pass SHG efficiency of any opticalbeams other than Gaussian beams. Unlike the disintegration of higher ordervortices in birefringent crystals, here, the use of quasi-phase matchingprocess enables generation of high quality vortices even at higher orders. Thegreen perfect vortices of all orders have temporal and spectral width of 507 fsand 1.9 nm, respectively corresponding to a time-bandwidth product of 1.02.

Efficient nonlinear generation of high power, higher order, ultrafast "perfect" vortices in green