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This study proposes two types of metasurfaces to adjust the phase of wavefront based on geometric phases. Specifically, a meta-atom etched by two different elliptic cylinders possesses more adjusted parameters and satisfies some demanding design conditions. Under the illumination of circularly polarized light, one of them, metalens, can focus the light with a focusing efficiency of 60 %. The other can generate vortex beams with an efficiency of ∼55%. Such metasurfaces can be used as planar optical components in biological, medical, and intelligent wearable fields.

A novel type of electro-optic scanner is presented which can satisfy the requirements for high speed and large-angle. It is a two-stage cascade system which consists of a fine scanning system implemented by using voltage-controlled refraction-based electro-optic deflectors and a coarse scanning using several LiNbO 3 electro-optic switch and polarization beam splitter system. The deflection angle can be enlarged by using the coarse-fine cascaded system. We demonstrate the design scheme of the proposed large-angle optical beam scanner. The system is analyzed and simulated theoretically. It is shown that proper design of the parameters of coarse-fine cascaded two-stage system can lead to an optimal beam scanner with enhanced performance of large angle and high speed. The analysis and observations will be valuable for the accurate design and fabrication of the novel optical scanning devices based on electro-optic effect.

Characteristic of electro-optic modulation of light propagating near the optic axis in a uniaxial crystal is well known but not for the cases of propagating bias the optic axis. In this paper, two pairs of LiNbO 3 crystal plates with the same sizes consist of an optical system in where the sum of geometrically optical length of o-ray and e-ray is equal. And then the characteristics of electro-optic modulation of light propagating bias the optic axis in LiNbO 3 are studied experimentally through a coherent received system. The additional phase shift caused by electro-optic effect is measured. The relation of phase shift varying with applied electric-field is reported when the angle between incident beam and the optic axis is 45o. Based on above experiments, a new 90o optical hybrid will be developed. Key words: LiNbO 3 crystal; electro-optic modulation; phase shift 1. INTRODUCTION The electro-optic effect of crystal is the basic of many electro-optic devices [1-4] . It plays an important role in the fields of optical information processing and optical communication. The properties of electro-optic modulation along optical axis are well known