A new scheme for recording a dynamic phase grating with an asymmetric profile in C60-doped homeotropically aligned nematic liquid crystal（NLC） was presented.An oblique incidence beam was used to record the thin asym...A new scheme for recording a dynamic phase grating with an asymmetric profile in C60-doped homeotropically aligned nematic liquid crystal（NLC） was presented.An oblique incidence beam was used to record the thin asymmetric dynamic phase holographic grating.The diffraction efficiency we achieved is more than 40%,exceeding the theoretical limit for symmetric profile gratings.Both facts can be explained by assuming that a grating with an asymmetric saw-tooth profile is formed in the NLC.Finally,physical mechanism and mathematical model for characterizing the asymmetric phase holographic grating were presented,based on the photo-refractive-like（PR-like） effect.展开更多
A high-efficiency technique for optical vortex(OV) generation is proposed and demonstrated. The technique is based on liquid crystal fork gratings with space-variant azimuthal orientations, which are locally controlle...A high-efficiency technique for optical vortex(OV) generation is proposed and demonstrated. The technique is based on liquid crystal fork gratings with space-variant azimuthal orientations, which are locally controlled via polarization-sensitive alignment layers. Thanks to the optical rewritability of the alignment agent and the dynamic image generation of the digital micro-mirror device, fork gratings can be instantly and arbitrarily reconfigured.Corresponding optical vortices carrying arbitrary azimuthal and radial indices are demonstrated with a conversion efficiency of 98.5%, exhibiting features of polarization control and electrical switching. The technique may pave a bright road toward OV generation, manipulation, and detection.展开更多
An ideal holographic 3D display should have the characteristics of large viewing angle,full color,and low speckle noise.However,the viewing angle of the holographic 3D display is usually limited by existing strategies...An ideal holographic 3D display should have the characteristics of large viewing angle,full color,and low speckle noise.However,the viewing angle of the holographic 3D display is usually limited by existing strategies,which vastly hinders its extensive application.In this paper,a large viewing angle holographic 3D display system based on maximum diffraction modulation is proposed.The core of the proposed system comprises the spatial light modulators(SLMs)and liquid crystal grating.We also present a new feasible scheme for the realization of large viewing angle holographic 3D display.This is achieved by considering the maximum diffraction angle of SLM as the limited diffraction modulation range of each image point.By doing so,we could not only give access to the maximum hologram size of the object,but also tune the reconstructed image of secondary diffraction by using a self-engineered liquid crystal grating.More importantly,the proposed maximum diffraction modulation scheme enables the viewing angle of the proposed system to be enlarged to 73.4°.The proposed system has huge application potential in the fields such as education,culture,and entertainment.展开更多
基金Project supported by the Science and Technology Programs of the Educational Committee of Heilongjiang Province,China(Grant No.12541730)the National Natural Science Foundation of China(Grant No.61405057)
文摘A new scheme for recording a dynamic phase grating with an asymmetric profile in C60-doped homeotropically aligned nematic liquid crystal（NLC） was presented.An oblique incidence beam was used to record the thin asymmetric dynamic phase holographic grating.The diffraction efficiency we achieved is more than 40%,exceeding the theoretical limit for symmetric profile gratings.Both facts can be explained by assuming that a grating with an asymmetric saw-tooth profile is formed in the NLC.Finally,physical mechanism and mathematical model for characterizing the asymmetric phase holographic grating were presented,based on the photo-refractive-like（PR-like） effect.
基金sponsored by the 973 programs (Nos. 2011CBA00200 and 2012CB921803)the NSFC programs (Nos. 61490714, 11304151, 61435008, and 61225026)+2 种基金the Ph.D. Programs Foundation of the Ministry of Education of China (No.20120091120020)the support from the Program for Changjiang Scholars and Innovative Research Team in University (No.IRT13021)PAPD
文摘A high-efficiency technique for optical vortex(OV) generation is proposed and demonstrated. The technique is based on liquid crystal fork gratings with space-variant azimuthal orientations, which are locally controlled via polarization-sensitive alignment layers. Thanks to the optical rewritability of the alignment agent and the dynamic image generation of the digital micro-mirror device, fork gratings can be instantly and arbitrarily reconfigured.Corresponding optical vortices carrying arbitrary azimuthal and radial indices are demonstrated with a conversion efficiency of 98.5%, exhibiting features of polarization control and electrical switching. The technique may pave a bright road toward OV generation, manipulation, and detection.
基金supported by the National Natural Science Foundation of China(62020106010,62275009,U22A2079,11974258).
文摘An ideal holographic 3D display should have the characteristics of large viewing angle,full color,and low speckle noise.However,the viewing angle of the holographic 3D display is usually limited by existing strategies,which vastly hinders its extensive application.In this paper,a large viewing angle holographic 3D display system based on maximum diffraction modulation is proposed.The core of the proposed system comprises the spatial light modulators(SLMs)and liquid crystal grating.We also present a new feasible scheme for the realization of large viewing angle holographic 3D display.This is achieved by considering the maximum diffraction angle of SLM as the limited diffraction modulation range of each image point.By doing so,we could not only give access to the maximum hologram size of the object,but also tune the reconstructed image of secondary diffraction by using a self-engineered liquid crystal grating.More importantly,the proposed maximum diffraction modulation scheme enables the viewing angle of the proposed system to be enlarged to 73.4°.The proposed system has huge application potential in the fields such as education,culture,and entertainment.
