Dr. SK Shaid-Ur Rahman Profile

Dr. SK Shaid-Ur Rahman

at HENSOLDT Optronics GmbH

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Profile Summary

Dr. Rahman is a system engineer in Hensoldt Optronics GmbH Germany. He received his PhD degree in Physics from University of Bremen in Germany. He joined Hensoldt Optronics in 2018 and works in the area of high performance space optics and imaging devices.

Publications (3)

Proceedings Article | 10 June 2024 Presentation

Design-based optimization of stray-light performance in a multispectral single aperture VIS/SWIR 2-chip camera

SK. Shaid-Ur Rahman, Bertram Achtner, Martin Hübner

Proceedings Volume PC13042, PC1304203 (2024) https://doi.org/10.1117/12.3013735

KEYWORDS: Short wave infrared radiation, Cameras, Stray light, Design and modelling, Zoom lenses, Reflection, Optical coatings, Light scattering, Infrared cameras, Imaging systems

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In this report we describe the effect of the uncoated and the coated grinded lens edges on the imaging performance of a high performance short wave infrared (SWIR) imager inside a fully achromatized multispectral SWIR/VIS zoom camera. The experimental result of various black coatings for the lens edges to prevent stray light in the VIS-SWIR spectrum is presented. SWIR cameras show significant advantages for the long range observation under different weather conditions (e.g, haze, mist or fog) due to the reduction of wavelength-dependent scattering extinction. The design of such a SWIR imager in a combined visible (450nm to 900nm) and the SWIR spectral (900nm to 1700 nm) camera with a continuous optical zoom factor of 15x for a limited space and relatively high pixel pitch of 15μm force the use of relatively high F-numbers to achieve narrow fields of view less than 1.5° with a reasonable resolution is a great challenge. Particularly unwanted stray light inside the camera significantly degrades the imaging performance of the SWIR sensor. A good anti-reflection coating on the lens elements improves the ghost images. However, especial prevention techniques are required to reduce the flare stray light that typically arises from reflection or scattering from non-optical path surfaces e.g., mount surfaces or edge surfaces of lenses. The mechanical baffles or stops can reduce these stray lights but it requires precise design and cost. The most common approach to prevent the stray light from the edges of the optical elements is to apply a black coating on the grinded lens edges. The available coatings for edge blackening are typically optimized for VIS spectral range and their blackening effect is limited in the SWIR spectrum by Fresnel reflection due to the index of refraction mismatch at the glass boundary. Here we have applied the appropriate black coating on the selective lens edges based on simulation as well as experiments and demonstrated the improved stray light performance in the SWIR channel.

Proceedings Article | 3 June 2022 Presentation + Paper

High performance all metal telescope for satellite based laser communication terminals

S. K. Shaid-Ur Rahman, Hans-Ulrich Wieland, Vladimir Burstein, Martin Hübner

Proceedings Volume 12121, 121210G (2022) https://doi.org/10.1117/12.2618787

KEYWORDS: Telescopes, Satellites, Satellite communications, Metals, Laser communications, Polarization, Optical instrument design, Mirrors, Aluminum, Wave plates

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Proceedings Article | 5 May 2021 Presentation + Paper

Performance verification of sun blocking filter for satellite based laser communication terminals

SK. Shaid-Ur Rahman, Stephane Bruynooghe, Michael Sundermann, Martin Hübner

Proceedings Volume 11740, 117400W (2021) https://doi.org/10.1117/12.2587926

KEYWORDS: Sun, Satellites, Satellite communications, Optical filters, Laser communications, Wavefronts, Polarization, Telescopes, Receivers, Transparency

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