  Spatially structured light has opened a wide range of opportunities for
enhanced imaging as well as optical manipulation and particle confinement.
Here, we show that phase-coherent illumination with superpositions of radial
Laguerre-Gauss (LG) beams provides improved localization for bright optical
tweezer traps, with narrowed radial and axial intensity distributions. Further,
the Gouy phase shifts for sums of tightly focused radial LG fields can be
exploited for novel phase-contrast strategies at the wavelength scale. One
example developed here is the suppression of interference fringes from
reflection near nano-dielectric surfaces, with the promise of improved
cold-atom delivery and manipulation.
