Mr. Mahmoud Essameldin Profile

Mahmoud Essameldin

PhD Student

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Publications (8)

Proceedings Article | 2 March 2020 Presentation + Paper

Fast measurement of optical components using a PSD for experimental ray tracing

T. Binkele, D. Hilbig, M. Essameldin, T. Henning, F. Fleischmann

Proceedings Volume 11287, 112870V (2020) https://doi.org/10.1117/12.2542252

KEYWORDS: Sensors, Calibration, Optical components, Ray tracing, Optical testing, Signal detection, Time metrology, Geometrical optics, Laser beam propagation

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Proceedings Article | 15 November 2019 Presentation + Paper

Measurement of form and mid-spatial-frequency errors of specular freeform surfaces

T. Binkele, D. Hilbig, M. Essameldin, F. Fleischmann, T. Henning, W. Lang

Proceedings Volume 11175, 1117513 (2019) https://doi.org/10.1117/12.2536887

KEYWORDS: Optics manufacturing, Optical components, Manufacturing, Optical testing, Ray tracing

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Proceedings Article | 21 June 2019 Paper

Precise measurement of known and unknown freeform surfaces using Experimental Ray Tracing

Tobias Binkele, David Hilbig, Mahmoud Essameldin, Thomas Henning, Friedrich Fleischmann, Walter Lang

Proceedings Volume 11056, 110561N (2019) https://doi.org/10.1117/12.2526025

KEYWORDS: Reflection, Cameras, Data modeling, Ray tracing, Matrices, Process modeling, Systems modeling, Sensors, Optical components

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Lenses and mirrors with freeform surfaces are the latest step in the evolution of optical components. However, the measurement of these components still challenges metrology. We have developed a gradient-based measurement technique that is able to measure freeform specular surfaces either if their form is known or not. The measurement of freeform surfaces is a challenge for every measurement system. Especially if the form of the surface is not known in advance. Our measurement system can measure continuous freeform surfaces with up to 10° deviation from a plane surface even if the surface model is not known in advance. Therefore, a ray, represented by a narrow laser beam, is targeted on the surface under test (SUT) under a certain angle. Affected by its slope, the surface reflects the ray in a new direction. This direction is measured by using a variation of Experimental Ray Tracing (ERT). This includes the measurement of the position of the reflected ray in two parallel planes. Calculating the difference of the position on these planes, the direction of the ray in relation to them can be calculated. Having the direction of the reflected ray, as well as the direction of the incident ray, one can determine the surface normal at the point of reflection. By moving the SUT, the incident ray targets on a different point on the SUT. Therewith, various points are investigated. Using appropriate integration methods, the surface can be reconstructed. Although, with the introduction of the incident ray under a certain angle comes the issue, that the point of reflection changes with the sag of the SUT. This leads to an unequal distant measurement grid of points of reflection even if the SUT has been moved to equal distant sample points. This shift has to be considered for the reconstruction of the surface. This issue is solved in different ways for known or unknown surfaces. For an unknown surface, the investigated sample points are transferred into a coordinate system where they are equal distant. This is the coordinate system of the incident beam. Performing the integration here and transferring the reconstructed surface back into the coordinate system of the SUT leads to the expected shift of the sample points. For a known surface, the expected surface form is taken into account to determine the sample point shift. Therewith, the difference between the measured surface normals and the expected normals can be calculated and the integration can be performed only on the normal residuals. By adding the residuals to the model, the surface can be reconstructed. The measurement technique described above has been implemented in an experimental setup. To show the abilities of this technique, we will show the process of the measurement of a known and an unknown surface using the same sample. The results will be evaluated and compared.

Proceedings Article | 4 March 2019 Paper

Characterization of gradient index optical components using experimental ray tracing

Tobias Binkele, Rebecca Dylla-Spears, Michael Johnson, David Hilbig, Mahmoud Essameldin, Thomas Henning, Friedrich Fleischmann

Proceedings Volume 10925, 109250D (2019) https://doi.org/10.1117/12.2511072

KEYWORDS: Refractive index, GRIN lenses, Printing, Optics manufacturing, Wavefronts, Ray tracing, Phase shifts, Diffraction, Interferometry, Gradient-index optics

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Proceedings Article | 28 May 2018 Paper

Problems of using the PMA adaptive mesh method in lens-array design for LED signal lighting

Mahmoud Essameldin, Friedrich Fleischmann, Thomas Henning

Proceedings Volume 10693, 106930P (2018) https://doi.org/10.1117/12.2314160

KEYWORDS: Lens design, Light sources, Light sources and illumination, Monte Carlo methods, Freeform optics, Light emitting diodes, LED lighting, Numerical analysis, Collimation, Geometrical optics

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Proceedings Article | 23 August 2017 Paper

Combining the transformation and the integration methods to design a refractive lens-array for signal lighting applications

Mahmoud Essameldin, Friedrich Fleischmann, Thomas Henning, Walter Lang

Proceedings Volume 10375, 103750Q (2017) https://doi.org/10.1117/12.2273809

KEYWORDS: Light sources, Light sources and illumination, Optical design, Lens design, Light, Geometrical optics, Freeform optics, Beam shaping, Ray tracing

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Proceedings Article | 20 February 2017 Paper

Design and evaluation of a freeform lens by using a method of luminous intensity mapping and a differential equation

Mahmoud Essameldin, Friedrich Fleischmann, Thomas Henning, Walter Lang

Proceedings Volume 10110, 1011006 (2017) https://doi.org/10.1117/12.2252357

KEYWORDS: Lens design, Light sources, Differential equations, Freeform optics, Geometrical optics, Optical design, Ray tracing, Tolerancing, Solids, Sensors, Spherical lenses, Light sources and illumination, Light

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Proceedings Article | 11 October 2016 Paper

Topography measurement of freeform specular surfaces using experimental ray tracing and radial basis functions

A. Alinoori, M. Essameldin, F. Fleischmann, T. Henning

Proceedings Volume 9961, 99610S (2016) https://doi.org/10.1117/12.2237665

KEYWORDS: Ray tracing, 3D metrology, Channel projecting optics, Information theory, Sensors, Reflection, Error analysis, Optical components, Tolerancing, 3D modeling

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Showing 5 of 8 publications

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