Dr. Lien Smeesters Profile

Dr. Lien Smeesters

Professor at Vrije Univ Brussel

SPIE Involvement:

Education and Outreach Committee | Conference Program Committee | Author

Area of Expertise:

optical design , UV-VIS-NIR spectroscopy , fluorescence , freeform optics , illumination optics

Publications (26)

Proceedings Article | 2 October 2024 Presentation

A visual tour through the nonimaging optics literature

Håkon J. D. Johnsen, Thomas Cooper, Lun Jiang, Lien Smeesters, Roland Winston

Proceedings Volume PC13132, PC1313201 (2024) https://doi.org/10.1117/12.3028858

KEYWORDS: Nonimaging optics, Visualization, Visual process modeling, Optics manufacturing, Manufacturing, Design, Data analysis

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Proceedings Article | 20 June 2024 Presentation + Paper

Broadband diffuse reflection spectroscopy and linear discriminant analysis enabling a non-destructive milk identification

Indy Magnus, Tarique Hasan, Hugo Thienpont, Lien Smeesters

Proceedings Volume 12999, 1299915 (2024) https://doi.org/10.1117/12.3017601

KEYWORDS: Reflection, Reflectance spectroscopy, Spectroscopy, Diffuse reflectance spectroscopy, Principal component analysis, Nondestructive evaluation, Integrating spheres, Reflectivity, Near infrared spectroscopy, Spectrum analysis

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Proceedings Article | 20 June 2024 Paper

Spectral sensing in the near-infrared and chemometrics for flour quality multi-analysis

L. Ciaccheri, L. Smeesters, A. A. Mencaglia, B. Adinolfi, A. G. Mignani

Proceedings Volume 12999, 129992K (2024) https://doi.org/10.1117/12.3021793

KEYWORDS: Proteins, Sensors, Chemometrics, Spectroscopy, Tunable filters, Reflectivity, Principal component analysis, Nondestructive evaluation, Statistical analysis

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Proceedings Article | 20 June 2024 Presentation + Paper

Fluorescence spectroscopy enhancing aflatoxin detection in solid food products: from laboratory setup towards handheld sensing units

Lien Smeesters

Proceedings Volume 13008, 1300802 (2024) https://doi.org/10.1117/12.3018019

KEYWORDS: Food inspection, Emission spectroscopy, Aflatoxins, Fluorescence, Contamination, Light sources and illumination, Fluorescence spectroscopy, Miniaturization

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Proceedings Article | 17 June 2024 Presentation + Paper

Cubesat multispectral space-based imaging spectrometer enhancing climate change monitoring

Matéo Yerlès, Luca Schifano, Steven Dewitte, Hugo Thienpont, Lien Smeesters

Proceedings Volume 13019, 130190U (2024) https://doi.org/10.1117/12.3017992

KEYWORDS: Spectroscopy, Spectral resolution, Spatial resolution, Telescopes, Visible radiation, Mirrors, Environmental monitoring, Design, Multispectral imaging, Climate change

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Proceedings Article | 17 June 2024 Presentation + Paper

Custom freeform optics for LiDAR applications: from design to fabrication

S. Sorgato, L. Smeesters, M. Vervaeke, K. Rochlitz, D. Rosseel, J. Verbaenen, S. Verlinski, H. Thienpont, J. Van Erps

Proceedings Volume 13019, 130191O (2024) https://doi.org/10.1117/12.3017565

KEYWORDS: Mirrors, LIDAR, Freeform optics, Fabrication, Design

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Proceedings Article | 17 June 2024 Presentation + Paper

Design and fabrication of polymer lightguides for optical sensing and illumination

S. Sorgato, L. Smeesters, M. Vervaeke, K. Rochlitz, D. Rosseel, J. Verbaenen, S. Verlinski, H. Thienpont, J. Van Erps

Proceedings Volume 13022, 1302205 (2024) https://doi.org/10.1117/12.3017471

KEYWORDS: Waveguides, Design, Optical surfaces, Fabrication, Nonimaging optics, Injection molding, Optical sensing

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Proceedings Article | 17 June 2024 Presentation + Paper

Broadband uniform illumination optics for industrial applications

Lien Smeesters, Indy Magnus, Hugo Thienpont, Simone Sorgato

Proceedings Volume 13022, 1302206 (2024) https://doi.org/10.1117/12.3017984

KEYWORDS: Light sources and illumination, Light emitting diodes, Lens arrays, Aspheric lenses, Industrial applications, Collimation, Optical design, Beam diameter, Freeform optics, Beam shaping

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Proceedings Article | 4 October 2023 Presentation + Paper

Freeform wide-field-of-view near-infrared imaging spectrometer for spaceborne climate monitoring

Lien Smeesters, Luca Schifano, Dries Rosseel, Jef Verbaenen, Hugo Thienpont, Francis Berghmans, Steven Dewitte, Michael Vervaeke

Proceedings Volume 12677, 126770C (2023) https://doi.org/10.1117/12.2677406

KEYWORDS: Freeform optics, Spectroscopy, Mirrors, Telescopes, Design and modelling, Manufacturing, Tolerancing, Environmental monitoring, Climatology, Spatial resolution

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Proceedings Article | 2 October 2023 Presentation + Paper

Halogen source illumination optimization using a beam shaping biconic lens array

Lien Smeesters, Dries Rosseel, Michael Vervaeke, Hugo Thienpont

Proceedings Volume 12666, 1266607 (2023) https://doi.org/10.1117/12.2677431

KEYWORDS: Illumination engineering, Beam homogenizers, Light sources and illumination, Lens arrays, Aspheric lenses, Design and modelling, Spherical lenses, Beam shaping, Optics manufacturing

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Proceedings Article | 14 September 2023 Paper

Optimization of freeform LED roadway lighting complying CIE standards

Lien Smeesters, Dries Rosseel, Michael Vervaeke, Hugo Thienpont

Proceedings Volume 12798, 127980F (2023) https://doi.org/10.1117/12.2691620

KEYWORDS: Illumination engineering, Light sources and illumination, Design and modelling, Roads, Freeform optics, Light emitting diodes, Ray tracing, LED lighting, Mathematical optimization, Lighting standards, Lens design

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Proceedings Article | 14 September 2023 Paper

Illumination design problem: the unicorn’s horn

William Cassarly, Julius Muschaweck, Henning Rehn, John Koshel, Lien Smeesters

Proceedings Volume 12798, 127980J (2023) https://doi.org/10.1117/12.3005730

KEYWORDS: Design and modelling, Light sources and illumination, Waveguides, Solids, Prisms, Hollow waveguides, Optical design, Total internal reflection, Refraction, Reflection

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Proceedings Article | 14 September 2023 Paper

Freeform wide-field-of-view imaging telescope improving spaceborne climate monitoring

Lien Smeesters, Luca Schifano, Dries Rosseel, Jef Verbaenen, Hugo Thienpont, Steven Dewitte, Francis Berghmans, Michael Vervaeke

Proceedings Volume 12798, 127980N (2023) https://doi.org/10.1117/12.2691627

KEYWORDS: Freeform optics, Diamond turning, Mirrors, Design and modelling, Telescopes, Modulation transfer functions, Environmental monitoring, Tolerancing, Space telescopes, Simulations, Optical surfaces

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Proceedings Article | 3 October 2022 Presentation + Paper

Design, tolerancing, and fabrication of a freeform lightguide based on the flow-line method

S. Sorgato, L. Smeesters, M. Vervaeke, K. Rochlitz, D. Rosseel, J. Verbaenen, H. Thienpont, T. Geernaert, J. Van Erps

Proceedings Volume 12220, 122200C (2022) https://doi.org/10.1117/12.2634433

KEYWORDS: Waveguides, Nonimaging optics, Optical fabrication, Tolerancing, Surface roughness, Prototyping, Optics manufacturing

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Proceedings Article | 17 May 2022 Presentation + Paper

Optical spectroscopy enhancing acrylamide sensing in French fries production increasing food safety

Lien Smeesters, Indy Magnus, Hugo Thienpont, Wendy Meulebroeck

Proceedings Volume 12139, 1213918 (2022) https://doi.org/10.1117/12.2621682

KEYWORDS: Spectroscopy, Reflectance spectroscopy, Light scattering, Reflection, Safety, Optical spectroscopy, Scattering, Reflectivity, Absorbance, Specular reflections

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Proceedings Article | 17 May 2022 Presentation + Paper

Towards a demonstrator setup for a wide-field-of-view visible to near-infrared camera aiming to characterize the solar radiation reflected by the Earth

Luca Schifano, Fabian Duerr, Francis Berghmans, Steven Dewitte, Lien Smeesters

Proceedings Volume 12138, 121380H (2022) https://doi.org/10.1117/12.2622144

KEYWORDS: Tolerancing, Aspheric lenses, Spherical lenses, Cameras, Lenses, Modulation transfer functions, Optical design, Solar radiation, Spatial resolution, Optics manufacturing

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Proceedings Article | 12 September 2021 Presentation + Paper

Compact wide field-of-view camera design for remote sensing of the Earth’s emitted thermal radiation

Luca Schifano, Lien Smeesters, Francis Berghmans, Steven Dewitte

Proceedings Volume 11859, 118590C (2021) https://doi.org/10.1117/12.2600084

KEYWORDS: Stray light analysis, Aspheric lenses, Infrared cameras, Remote sensing, Satellites, Tolerancing, Cameras, Sensors, Modulation transfer functions, Optical design, Lenses, Image quality, Monte Carlo methods, Optics manufacturing

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Proceedings Article | 12 September 2021 Presentation + Paper

Advanced high-power laser diode combination design for laser scanning applications

L. Smeesters, H. Thienpont, W. Meulebroeck

Proceedings Volume 11874, 118740E (2021) https://doi.org/10.1117/12.2597141

KEYWORDS: Semiconductor lasers, Beam splitters, Mirrors, Collimation, Aspheric lenses, Laser scanners, Laser cutting, High power lasers, Illumination engineering, Beam shaping, Polarizing prisms

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Proceedings Article | 12 September 2021 Presentation + Paper

Beam-shaping lens for high-power laser cutting applications

L. Smeesters, S. Donner, H. Thienpont, M. Vervaeke

Proceedings Volume 11871, 118710C (2021) https://doi.org/10.1117/12.2597148

KEYWORDS: Semiconductor lasers, Laser cutting, Aspheric lenses, Tolerancing, Manufacturing, Lens design, High power lasers, Freeform optics, Beam shaping, Light sources and illumination

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Laser cutters are currently finding their way from industrial environments to home-use applications, driving the development towards low-cost and compact systems. We therefore target the design of a single beam-shaping lens for use in laser cutting applications, enabling the miniaturization of the laser scanning head while pursuing optimal cutting performance. Particularly, we target the design of a beam shaping lens for use with a high-power 450 nm laser diode (5.0 Watt, 14° x 46° beam divergence), enabling to transform the divergent elliptical laser diode beam into a circular focused spot, while maximizing the depth-of-focus. We cover the complete development chain, starting from the characterization and modelling of the laser diode, to the optical design, optimization and tolerancing of the focusing lens, and the manufacturing and demonstration of the laser cutting system. The optimized beam-shaping lens features a circular focused spot diameter <100 μm over a depth-of-focus of 4.8 mm. In contrast to the current laser diode circularization and focusing designs, comprising a combination of cylindrical and plano-convex lenses, we only use a single aspheric biconic lens, giving rise to a more compact design. A tolerance analysis was included on both the optical and mechanical parameters, enabling to evaluate the design for manufacturing. Following, the novel beam-shaping lens was manufactured using ultraprecision diamond turning, and afterwards characterized using a coordinate measurement machine. Finally, the performance is evaluated in a proof-of-concept demonstrator, validating the circular illumination beam and improved cutting performance. We successfully demonstrated the operation of our novel beam-shaping lens, featuring the beam circularization and focusing using a single lens, optimized for use in compact laser cutting devices. This novel lens design paves the way towards a further miniaturization of desktop laser cutters, while showing an excellent laser cutting performance, including an improved cutting resolution and depth-of-focus, enabling a wider range of materials and extended material thicknesses.

Proceedings Article | 11 June 2021 Open Access

Towards a next-generation Earth Radiation Budget radiometer by optimization of the cavity geometry and coating

Luca Schifano, Lien Smeesters, Francis Berghmans, Steven Dewitte

Proceedings Volume 11852, 118520O (2021) https://doi.org/10.1117/12.2599171

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Proceedings Article | 20 September 2020 Presentation + Paper

VACNT versus Black Velvet: a coating analysis for the next-generation Earth Radiation Budget radiometer

Luca Schifano, Lien Smeesters, Wendy Meulebroeck, Francis Berghmans, Steven Dewitte

Proceedings Volume 11531, 115310J (2020) https://doi.org/10.1117/12.2573996

KEYWORDS: Coating, Radiometry, Sensors, Absorbance, Radio optics, Climatology, Carbon nanotubes, Space operations, Geometrical optics, Scattering

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Climate on Earth is determined by the Earth Radiation Budget (ERB), which quantifies the incoming and outgoing radiative energy fluxes at the top-of-atmosphere (TOA). The ERB can be monitored from space by non-scanning wide field-of-view radiometers (WFOV), or by scanning narrow field-of-view radiometers. Recently, WFOV radiometers have gained renewed interest as illustrated by the development of the RAVAN and SIMBA 3U CubeSats. RAVAN uses a Vertically Aligned Carbon Nanotubes (VACNT) coating, while the SIMBA CubeSat uses a novel cavity-based geometry with a Black Velvet coating. Both VACNT and Black Velvet are diffuse coatings, but when applied to flat sensors, the VACNT coating has a significantly lower reflectivity in comparison to classic diffuse or specular black coating materials. When used on a cavity radiometer, it is currently unclear if a VACNT coating would improve the measurement accuracy compared to other diffuse coatings, such as Black Velvet. In this paper, we therefore investigate the potential benefits of using the VACNT coating as an alternative for Black Velvet, in our in-house developed radiometer. Our analysis includes the evaluation of the influence of the cavity geometry as well as the coating absorption factor. The comparison of the VACNT with the Black Velvet coating is based on the absorption factor of the cavity that is determined using radiation view factor calculations. Scattering and stray-light analyses are carried out using commercially available ray-tracing software (ASAP R, Breault Research). We evaluated whether the coating or the geometry is the main contributing factor to the performance of the radiometer. As a conclusion, we observed that for cavity-type radiometers, the difference in the cavity absorption factor between Black Velvet and VACNT becomes negligible, favoring the use of Black Velvet, since Black Velvet has a long space heritage and appears more user friendly from a fabrication point of view, as it can be deposited in an easier and more reproducible manner on the radiometer cavity walls, including non at surfaces.

Proceedings Article | 28 May 2018 Paper

Design of an optical refocusing illumination system for use in laser-scanning devices

L. Smeesters, W. Meulebroeck, H. Thienpont

Proceedings Volume 10693, 1069302 (2018) https://doi.org/10.1117/12.2309856

KEYWORDS: Imaging systems, Optical scanning systems, Optical design, Lens design, Liquid lenses, Aspheric lenses, Liquids

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Proceedings Article | 29 April 2016 Paper

One- and two-photon induced fluorescence spectroscopy enabling the detection of localized aflatoxin contamination in individual maize kernels

L. Smeesters, W. Meulebroeck, S. Raeymaekers, H. Thienpont

Proceedings Volume 9899, 98990X (2016) https://doi.org/10.1117/12.2227467

KEYWORDS: Contamination, Fluorescence spectroscopy, Optical sensing, Spectrum analysis, Tunable lasers, Laser induced fluorescence, Luminescence, Optical spectroscopy, Spectroscopy, Signal detection, Absorbance, Visualization, Ultraviolet radiation, Absorption

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Proceedings Article | 25 September 2014 Paper

Proof-of-concept demonstration of a miniaturized multi-resolution refocusing imaging system using an electrically tunable lens

L. Smeesters, G. Belay, H. Ottevaere, Y. Meuret, Michael Vervaeke, J. Van Erps, H. Thienpont

Proceedings Volume 9192, 91920G (2014) https://doi.org/10.1117/12.2061296

KEYWORDS: Image resolution, Imaging systems, Multichannel imaging systems, Image sensors, Modulation transfer functions, Spatial resolution, Image quality, Liquids, Liquid lenses, Lens design

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Proceedings Article | 5 September 2014 Paper

The use of one- and two- photon induced fluorescence spectroscopy for the optical characterization of carcinogenic aflatoxins

L. Smeesters, W. Meulebroeck, S. Raeymaekers, H. Thienpont

Proceedings Volume 9198, 919803 (2014) https://doi.org/10.1117/12.2061314

KEYWORDS: Luminescence, Fluorescence spectroscopy, Tunable lasers, Ultraviolet radiation, Absorption, Signal detection, Spectrum analysis, Absorbance, Chemical analysis, Crystals

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Proceedings Article | 15 May 2014 Paper

Refocusing capabilities in a miniaturized multi-channel multi-resolution imaging system using a tunable lens

L. Smeesters, Gebirie Belay, H. Ottevaere, Youri Meuret, H. Thienpont

Proceedings Volume 9138, 913809 (2014) https://doi.org/10.1117/12.2051936

KEYWORDS: Imaging systems, Modulation transfer functions, Image resolution, Liquid lenses, Liquids, Image sensors, Image quality, Spatial resolution, Multichannel imaging systems, Lens design

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Showing 5 of 26 publications

Conference Committee Involvement (2)

Nonimaging Optics: Efficient Design for Illumination and Concentration XX

3 August 2025 | San Diego, California, United States

Nonimaging Optics: Efficient Design for Illumination and Concentration XIX

18 August 2024 | San Diego, California, United States

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