Superresolution using a vertical-cavity surface-emitting laser (VCSEL) with a high-order Laguerre-Gaussian mode

A vertical-cavity surface-emitting laser (VCSEL) is current-annealed to ope rate in the high order (0, 4) Laguerre mode, and this source is used in a s uperresolution setup to achieve a spot size smaller than the classical diff raction limit. Theory predicts a reduction down to 51% of the classical lim it in each dimension (i.e. 4 x reduction in area), and a reduction down to 65% (i.e. 2.5 x reduction in area) is experimentally demonstrated with a si gnal-to-noise ratio of > 10 dB between the main-lobe and the side-lobe inte nsities.