Abstract: This article presents an efficient synthesis method for generating vortex beams based on donut-shaped orbital angular momentum (OAM) metasurfaces. It not only allows one to synthesize the ...

Tiny bone fragments from Alaska suggest birds started breeding and nesting in the Arctic 30 million years earlier than ...

Spring in the Arctic brings forth a plethora of peeps and downy hatchlings as millions of birds gather to raise their young.