  Magnetic skyrmions are topologically nontrivial spin textures which hold
great promise as stable information carriers in spintronic devices at the
nanoscale. One of the major challenges for developing novel skyrmion-based
memory and logic devices is fast and controlled creation of magnetic skyrmions
at ambient conditions. Here we demonstrate the single ultrafast (35-fs) laser
pulse-induced generation of skyrmion bubbles and skyrmion bubble lattices from
a ferromagnetic state in sputtered ultrathin magnetic films at room
temperature. The skyrmion bubble density increases with the laser fluence in a
controlled way, and it finally becomes saturated, forming disordered hexagonal
lattices. Moreover, we present that the skyrmion bubble lattice configuration
leads to enhanced topological stability as compared to isolated skyrmions,
suggesting its promising use in data storage. Our findings shed light on the
optical approach to the skyrmion bubble lattice in commonly accessible
materials, paving the road toward the emerging skyrmion-based memory and
synaptic devices.
