| Popis: |
An all-dielectric, subwavelength grated based metal-oxide nano-hair structure for optical vortex beam generation has been presented in the paper. The nano-hair structure fabricated with alternating layers of alumina/hafnia on a fused silica substrate has a high diffraction efficiency of ~90% around the design wavelength, λ(o) = 1.55 μm and is insensitive to the polarization of the incident optical beam. The phase in transmission of these devices are controlled by azimuthally varying the fill fraction of the subwavelength grating. Realization of phase optical elements in an all-dielectric platform, based on subwavelength gratings offering full 0-2π phase modulation, is important for miniaturization and integration of conventional refractive optical elements. |
