Three-plane phase-only computer hologram generated with iterative Fresnel algorithm

Phase-only hologram generation based on integral imaging and its enhancement in depth resolution

“…3(a) and (b). They occur because the depth interval between two planes, ∆z, is too small [5] . This problem becomes severe as the distance between the two depth planes becomes smaller.…”

“…We use the elemental image set for the purpose of generating depth-slice images, which is the basic information for multi-plane phase-only hologram [4] . The individual depth-slice image is placed at the proper depth plane and converted into phase-only hologram using IFTA for multiple planes [5] . In the IFTA, each target image is propagated into the next depth plane, and the phase distribution in the complex amplitude of the propagated wave is extracted to be combined with the new target image.…”

“…Since phase-only modulation devices are widely used due to their efficiency, it is an important issue to make constant amplitude profile in the CGH. To satisfy the constant amplitude distribution, we used the modified IFTA for the multi-plane images [5] . In this letter, we verify the limitation of our previous work, and propose an enhancement method for generating hologram with higher depth resolution.…”

Three-dimensional holographic lithography by an iterative algorithm

“…Unconstrained areas remain unaltered. As discussed in [8], low regions cannot be set to zero as this would lead to a loss of phase information between propagation steps. The high/low ratio was chosen so as to enforce as large a contrast as possible without overconstraining the requirements on the image field.…”

“…These methods are usually applied to a single planar image. To extend this to 3D surfaces, we have implemented a multiplane modification similar to [6][7][8], with further constraints. Specifically: exclusive use of the AS method for propagation to ensure valid patterns over short propagation distances, maintaining a constant sum of squared amplitude values when correcting the hologram in order to help maintain the stability of the iteration, and defining a set of constraints that can result in a useful exposure pattern.…”