Tighter spots of light with superposed orbital angular momentum beams

Abstract

The possibility of focusing light to an ever tighter spot has important implications for many applications and fields of optics research, such as nano-optics and plasmonics, laser-scanning microscopy, optical data storage and many more. The size of lateral features of the field at the focus depends on several parameters, including the numerical aperture of the focusing system, but also the wavelength and polarization, phase and intensity distribution of the input beam. Here, we study the smallest achievable focal feature sizes of coherent superpositions of two co-propagating beams carrying opposite orbital angular momentum. We investigate the feature sizes for this class of beams not only in the scalar limit, but also use a fully vectorial treatment to discuss the case of tight focusing. Both our numerical simulations and our experimental results confirm that lateral feature sizes considerably smaller than those of a tightly focused Gaussian light beam can be observed. These findings may pave the way for improving the resolution of imaging systems or may find applications in nano-optics experiments.

6 pages, 3 figures

References in corpus (8)

• Optical spin-to-orbital angular momentum conversion in inhomogeneous anisotropic media
• Optical ferris wheel for ultracold atoms
• Influence of Atmospheric Turbulence on Optical Communications using Orbital Angular Momentum for Encoding
• Divergence of an orbital-angular-momentum-carrying beam upon propagation
• The role of the angular momentum of light in Mie scattering. Excitation of dielectric spheres with Laguerre-Gaussian modes
• Tailoring the excitation of localized surface plasmon-polariton resonances by focusing radially-polarized beams
• On Small Beams with Large Topological Charge
• Towards an optical far-field measurement of higher-order multipole contributions to the scattering response of nanoparticles

Cited by in corpus (4)

• Reduced volume and reflection for bright optical tweezers with radial Laguerre-Gauss beams
• Optical Angular Momentum Manipulations in a Four Wave Mixing Process
• On Small Beams with Large Topological Charge II: Photons, Electrons and Gravitational Waves
• Orbital angular momentum beam generation using a free-electron laser oscillator