Impact Statement:We think that energy balance is essential in systems in which optical power or signal-to-noise ratio is limited. Most of the literature using OAM wrongly assumes that the...Show More
Abstract:
The generation of optical beams with multiple, mutually coherent orbital-angular-momentum (OAM) modes using phase gratings is analyzed from the perspective of energy dist...Show MoreMetadata
Impact Statement:
We think that energy balance is essential in systems in which optical power or signal-to-noise ratio is limited. Most of the literature using OAM wrongly assumes that the superposition of coherent vortex fields on diffracting devices will generate the desired, uniform composition. To address the problem of energy imbalance, the vortex superposition is analyzed using a LG basis adapted to the beam, using different waists and amplitudes.
Abstract:
The generation of optical beams with multiple, mutually coherent orbital-angular-momentum (OAM) modes using phase gratings is analyzed from the perspective of energy distribution and radial mode composition. We show that phase gratings designed with equally weighted Laguerre-Gauss (LG) modes will generate beams with uneven energy distribution among OAM components. This unwanted outcome cannot be corrected by adjusting the width of the illuminating beam. We propose a way to design phase gratings that will produce a uniform energy distribution among the constituent OAM states after illumination while minimizing the content of high radial modes. This method is based on a generalized definition for the LG modes that take advantage of the freedom to select their radial scales.
Published in: IEEE Photonics Journal ( Volume: 10, Issue: 2, April 2018)
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