Research On Spatial Light Modulation Technologies And Applications Based On Micro-Nano Optical Devices

The application of optical technology demands efficient exploitation of the orthogonal dimensions of light-wave.In particular,the exploitation of the transverse spatial distribution of the light-wave drives forward the important fields of optical communication,imaging,quantum information,sensing,etc.The efficient exploitation requires a simultaneous,independent,and continuous modulation of the spatial amplitude,phase,and polarization profile of the light-wave.Compared to conventional spatial light modulation elements with large volume and low resolution,the micro-nano devices can modulate the spatial light with high resolution,small size,short action distance and high integration.As a result,this dissertation concentrates on the planar micro-nano optical elements based on spatial light modulation and their applications,elaborated as follows:(1)The physical mechanism of geometric phase metasurfaces is studied.For the error induced by the rotational symmetry breaking of the geometric phase metasurface,its physical source is analyzed and its influence is studied.Furthermore,taking several typical applications as examples,the performance of geometric phase devices under different incident conditions is investigated.Finally,the corresponding optimization guideline is provided for several practical applications.(2)The broadband full-modulation geometric phase metasurfaces are designed and fabricated.To solve the problem that the conventional metasurface can not fully tailor spatial light in broadband,the parallel-tasking method is proposed.Indeed,the rotation angle of each geometric phase metasurface unit is divided into several sub angles,which are used for the modulation of the amplitude,phase and polarization distribution,respectively,thus to realize the simultaneous,independent and continuous modulation of the spatial amplitude,phase and polarization profile of the incident beam.Finally,the full-modulation metasurface is designed and fabricated,which can produce the selective multi-level vector beam as a typical example to demonstrate the full-modulation of light.(3)The multi-dimensional multiplexing hologram is demonstrated by the fullmodulation geometric phase metasurface.To address the low capacity and weak fidelity problems of the conventional meta-holograms,the multi-dimensional multiplexing metaholograms using full-modulation dielectric geometric-phase metasurfaces is proposed and demonstrated.This strategy uses multiple dimensions of light to multiplex the hologram to increase the capacity and employs the full-modulation metasurface to record the light field with high fidelity.The meta-hologram realizes the multiplexing of multiple holograms by using polarization and propagation direction dimensions,which can obtain different holographic images according to different input and output conditions.Compared with the traditional meta-hologram,the proposed method not only can significantly increase the information capacity,but also can reduce the crosstalk and enhance the energy uniformity of each channel.(4)The multi-scene applications of multi-dimensional spatial light field modulation based on micro-nano devices are studied.Firstly,a compact and low-energy consumption orbital angular momentum multiplexing wireless optical communication prototype for the realistic underwater environment is designed and demonstrated by employing the liquid crystal photo-alignment Q-plate.Then,the multi-tasking geometric phase device is applied to measure the polarization state of coherent light in real-time and broadband.Finally,the self-referenced vortex interferometry micro-imaging system is realized by liquid crystal photo-alignment elements.Using the proposed system,the three-dimensional topographies of a sample surface are accurately measured and recovered.