In this paper, we present a new and practical method for achieving real-time wavefront measurement, dramatically increasing the resolution, dynamic range of Shack-Hartmann wavefront sensor and improving the wavefront reconstruction quality. In proposal method, a liquid crystal display panel (LCD) for the generation of an array of Fresnel microlenses is used instead of the static microlens array of the conventional Shack-Hartmann type sensor
An off-axis holographic microlens array is designed instead of the normal microlens array to increase the effective array and then the dynamic range. The focus properties of the off-axis lens are studied.
In this paper the research of the real-time three-dimensional holographic imaging system which uses liquid crystal panels to display the computer generated Fresnel holograms for reconstructed 3D images is described. The reconstructed effects are related to each step of the process and the characteristics of the devices. The contradictions between the quantization of holographic numerical data and the properties of the display device are the important reasons for the reconstruction errors. A new algorithm for calculating point holograms is proposed for reducing the reconstruction errors. Finally the original experimental result is given.
A new fast algorithm using the “host” Fresnel zone plate was proposed to improve the computational efficiency of computer-generated hologram (CGH) for 3D objects. By reading .3DS files, the spatial position information of each point of the 3D object was obtained directly. With the illumination of plane wave, the “host” Fresnel zone plate of a single point could be equal to all points located in the same depth plane - as the Fresnel zone plate was translated and superimposed along the horizontal and vertical axes. Consequently, the hologram of a 3D object could be built up by superimposing different Fresnel zone plates in the corresponding depth planes. For a digital object composed of 1060 points, it cost about 83s to generate a hologram of 1024*768 pixels. The CGH of 3D objects with the results of the reconstruction was presented in this paper, which proved the feasibility of this algorithm.