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Free keywords:
GRATINGSOptics; nonlinear optics; nonlinear slow-mode waveguides; stimulated Raman
scattering; self-phase modulation; Silicon Raman amplifier;
Abstract:
A discontinuous space variant sub-wavelength dielectric grating is designed and fabricated for generating radially polarized light in visible region (lambda = 632.8 nm). The design is based on sub-wavelength silicon nitride structures introducing a retardation of pi/2 by form birefringence, with space variant orientation of the optical axis. The pattern is divided into concentric ring segments with constant structural parameters, therefore reducing electron-beam writing time significantly. The design avoids the technological challenges encountered in the generation of a continuous space variant grating while maintaining good quality of the resulting polarization mode. [DOI: http://dx.doi.org/10.2971/jeos.2011.11041]
