Off-plane computer-generated waveguide hologram
Off-plane computer-generated waveguide hologram
复制标题
离面计算机生成的波导全息图
DOI：
10.1109/2944.577367
复制
发表时间：
1996
影响因子：
4.9
通讯作者：
T. Suhara
中科院分区：
文献类型：
--
作者：
Ming Li;J. Bengtsson;M. Hagberg;A. Larsson;T. Suhara
介绍了离面计算波导型全息图的原理、设计、制作和评价。该全息图结构由矩形元件阵列组成，每个矩形元件包含一个波导光栅耦合器。矩形元件的作用是双重的：出射光导波和引入相移。每个矩形单元的相移可以通过控制沿导波传播方向的栅槽的位错来确定。此外，OP-CGWH的相位图可以使用许多现有的计算全息图(CGH)算法来设计，例如迭代傅里叶变换算法(IFTA)。给出了一种波导阵产生器的设计实例，该产生器在输出类高斯型入射导波的同时，在自由空间中产生光斑阵列。这种基于AlGaAsGaAs光波导的OP-CGWH器件是采用电子束光刻和反应离子束刻蚀的方法制作的。给出了实验结果，验证了该方法的有效性。所制作的OP-CGWH阵列发生器的均匀性误差和功率效率分别约为8%和30%。
We present the theory, design, fabrication and evaluation of off-plane computer-generated waveguide holograms (OP-CGWHs). The hologram structure is composed of an array of rectangular elements each containing a waveguide grating coupler. The function of the rectangular elements is twofold: outcoupling the guided optical wave, and introducing phase shift. The phase shift of each rectangular element can be determined by controlling the dislocation of the grating grooves along the guided wave propagation direction. In addition, the phase pattern of the OP-CGWH can be designed using many existing algorithms for computer-generated holograms (CGH), such as the iterative Fourier transform algorithm (IFTA). A design example is presented for a waveguide array generator, which outcouples a Gaussian-like incident guided wave and simultaneously produces an array of spots in free space. Such an OP-CGWH device, based on an AlGaAs-GaAs waveguide, was fabricated using electron-beam lithography and reactive ion beam etching. Experimental results are presented that demonstrate the effectiveness of the proposed idea. The uniformity error and the power efficiency of the fabricated OP-CGWH array generator were measured to be approximately 8% and 30%, respectively.