Variable Fresnel Zone Pattern

Lohmann, Adolf W.; Paris, D. P.

doi:10.1364/ao.6.001567

Cited by 72 publications

(27 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[6][7][8][9] In such cases, the rigorous numerical representation of the reconstructed-image as described in eq. (11) has not been used.…”

Section: Encoding Of the Lohmann-type Cgh Using Inverse Fourier Transmentioning

confidence: 99%

“…CGHs can be broadly classified into two major types, namely, the pixel-oriented CGHs [1][2][3][4][5] and the cell-oriented CGHs, which we call the Lohmann-type CGHs 6,7) in this paper. These two major types differ in unit-cell structure.…”

Section: Introductionmentioning

confidence: 99%

“…Lohmann-type CGHs are conventionally encoded as Fourier-transformed holograms, 6,7) similarly to pixel-oriented CGHs. This encoding method is exactly true for the pixeloriented CGHs, but only approximately true for the Lohmann-type CGHs.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Enhancement of the Lohmann-type computer-generated hologram encoded by direct multilevel search algorithm

Tamura

Torii

2012

OPT REV

View full text Add to dashboard Cite

An optimization-coding algorithm is required to produce high-quality computer-generated holograms (CGHs). For such a purpose, we have developed the direct multilevel search (DMS) algorithm using the rigorous reconstructed-image representation for encoding Lohmann-type CGHs. However, it required much time owing to the one-by-one search process: the optimal amplitude and phase must be selected from many multilevel amplitudes and phases. To solve this problem, we have established the AE1-trial search method, which can greatly reduce the trial search number: searches are limited only to the minimum shifts in amplitude and phase instead of all the possible shifts. Moreover, the DMS algorithm that incorporates the oversampled encoding method has been verified to be effective for reducing the optical reconstructed-image error by preparing the CGHs using electron-beam lithography.

show abstract

“…[6][7][8][9] In such cases, the rigorous numerical representation of the reconstructed-image as described in eq. (11) has not been used.…”

Section: Encoding Of the Lohmann-type Cgh Using Inverse Fourier Transmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Enhancement of the Lohmann-type computer-generated hologram encoded by direct multilevel search algorithm

Tamura

Torii

2012

OPT REV

View full text Add to dashboard Cite

show abstract

“…4 The same is also true for moiré effects between repetitive layers (i.e., between geometric transformations of periodic layers). [5][6][7][8][9][10] It is also known that the superposition of aperiodic layers, such as random dot screens, may give rise to a different type of moiré pattern, which consists of a single structure resembling a top-viewed funnel or a distant galaxy in the night sky [see, for example, Figs. 1(c) and 1(e)].…”

Section: Introductionmentioning

confidence: 99%

Dot trajectories in the superposition of random screens: analysis and synthesis

Amidror

2004

J. Opt. Soc. Am. A

View full text Add to dashboard Cite

Moiré effects that occur in the superposition of aperiodic layers such as correlated random dot screens are known as Glass patterns. One of the most interesting properties of such moiré effects, which clearly distinguish them from their periodic counterparts, is undoubtedly the appearence in the superposition of intriguing microstructure dot alignments, also known as dot trajectories. These dot trajectories may have different geometric shapes, depending on the transformations undergone by the superposed layers. In the case of simple linear transformations such as layer rotations or layer scalings, the resulting dot trajectories are rather simple (circular, radial, spiral, elliptic, hyperbolic, linear, etc.); but in more complex layer transformations the dot trajectories can have much more interesting and surprising shapes. A full mathematical analysis of the dot trajectories, their morphology, and their various properties is provided. Furthermore, it is shown how the approach also allows us to synthesize correlated random screens that give in their superposition dot trajectories having any desired geometric shapes. Finally, it is also explained why such dot trajectories are visible only in superpositions of aperiodic screens but not in superpositions of periodic screens.

show abstract

“…Lohmann [14][15][16][17] and Alvarez [18,19] re-discovered independently Kitajima's technique for implementing varifocal lenses. By employing helical wavefronts, one can generate variable Fresnel patterns [20,21], as well as vortex lenses [22].…”

mentioning

confidence: 99%