Diffractive Optics: Scalar And Non-Scalar Design Analysis

Gallagher, Neal C.; Sohail, S.; Naqvi, H.

doi:10.1117/12.951484

Cited by 5 publications

(2 citation statements)

References 7 publications

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“…(The frequency of the lens varies linearly from the center of the lens, and most of the energy of the laser is contained near the axis.) Finally, full vector analysis of radiatioi from simi)le gratings [4] show that scalar (Fresnel and Kirchhoff) design can be used for structures with dimensions on the order of a wavelength, in accordance with the discussion provided above, and that for far field radiation (more than 100 wavelengths from the grating) such as we consider, the usefulness of scalar wave theory extends to structures on the order of half a wavelength. We use a parametric approach to model the laser.…”

Section: Generalmentioning

confidence: 63%

<title>Focusing and collimating laser diodes and laser diode arrays</title>

Coetzee

Casasent

1991

Miniature and Micro-Optics: Fabrication and System Applications

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Computer generated holograms for laser diode (LD) focusing are described. A quantitative description of design tradeoffs is given. The LD parameters (not parallel input light) are included. Multiple CGH lenses, non-equal focal lengths in x and y, positive and negative focal lengths in the same lens, circular focal spots and equal variance focal spots, attention to focusing angles, and 1-D LD array collimation for optical data processing applications are considered.

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Section: Generalmentioning

confidence: 63%

<title>Focusing and collimating laser diodes and laser diode arrays</title>

Coetzee

Casasent

1991

Miniature and Micro-Optics: Fabrication and System Applications

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“…can be written in phasor notation as (9) where the and represent amplitude and phase matrix elements, respectively.…”

Section: A Wire Segment Layoutmentioning

confidence: 99%

Null holographic test structures for the measurement of overlay and its statistical variation

AbuGhazaleh

Christie

Agrawal

et al. 2000

IEEE Trans. Semicond. Manufact.

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Results are presented on the use of null wire segment holograms for the in-line assessment of mask alignment errors in the integrated circuit fabrication process. Process variations are detected by measuring the light intensity generated by a hologram designed to project a null image. To detect alignment errors, the mask for the wire segment hologram (WSH) is distributed between two mask layers. If the two sets of diffracting structures defined by the masks are transferred to the wafer with perfect registration, the result is an area of light cancellation (null) in the image plane. Increased mask misalignment leads to imperfect wavefront cancellation, which is manifested as an increase in light intensity in the null region. In order to characterize misalignment under controlled conditions, the two portions of the holographic test structure were initially recombined into a single structure but with intentional misalignment between the two portions designed into the mask. The technique was then used to characterize the alignment errors between two separate masks with the actual fabricated offsets measured using atomic force microscopy. Initial results indicate the technique is capable of resolving 0.1-m mask misalignment for a 1-m minimum feature process.

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