Conference Program 2026

Nonimaging Optics XXI is part of SPIE Optics + Photonics 2026. The official SPIE program listing is available on the SPIE conference page.

Invited Speaker

Felix Göhring

German Aerospace Center (DLR), Institute of Solar Research

Felix Göhring is a mechanical engineer and research group leader at the German Aerospace Center (DLR), Institute of Solar Research. He leads the operation and development of large-scale solar thermal research facilities, including the Solar Power Tower Jülich and the Multi-Focal Tower. His work focuses on high-temperature solar technologies, power plant engineering, and the integration of innovative thermal processes.

Read full bio

Since joining DLR in 2009, he has held roles as scientist, project engineer, and group leader, managing multidisciplinary teams of researchers and engineers. He has led major infrastructure and R&D projects, including the development of the Multi-Focal Tower Jülich and federally funded projects addressing concentrating solar technologies and electric heating systems for high-temperature applications.

Felix holds a degree in Mechanical Engineering with a specialization in energy technologies from RWTH Aachen University.

Program

Monday, 24 August 2026

Opening Remarks and Conference Overview

8:30 AM

Opening Remarks and Conference Overview

Håkon Jarand Dugstad Johnsen, Norwegian Univ. of Science and Technology (Norway)

Theoretical Foundations and Modeling

8:40 AM

Can asymmetric optics surpass C = 1/sinθ? A formalization of the definition of concentration ratio of asymmetric nonimaging optics

Thomas A. Cooper, York Univ. (Canada)

9:00 AM

Angular extent and flowline vector field

Lun Jiang, Arisen Sun (United States)

9:20 AM

Thermodynamic convergence of higher order optical problems using flowlines

Alex G. Lehmann, Nicholas J. Ekins-Daukes, Mark Keevers, The Univ. of New South Wales (Australia)

Coffee Break 9:40 AM - 10:10 AM

Solar Concentration and Receivers

10:10 AM

A modular secondary concentrator for high-flux solar testing: design, experimental validation, and industrial scalability at 10 megawatts (Invited Paper)

Felix Göhring, Kai Wieghardt, Maximilian Drexelius, Deutsches Zentrum für Luft- und Raumfahrt e.V. (Germany)

10:40 AM

Angularly selective cavities for high-temperature solar receivers

Håkon Jarand Dugstad Johnsen, Norwegian Univ. of Science and Technology (Norway)

11:00 AM

Parametric design of nonimaging concentrators by direct application of the edge-ray principle in CAD

Haoyun Zhao, Upper Canada College (Canada); Thomas A. Cooper, York Univ. (Canada)

11:20 AM

Analytic design of aspheric linear Fresnel lens for dehydrating process

Martín Jiménez-Rodríguez, Maximino A. Avendaño-Alejo, Univ. Nacional Autónoma de México (Mexico); Gabriel Castillo-Santiago, Univ. del Istmo (Mexico); Ismael Velázquez-Gómez, Osvaldo Ponce-Hernández, Univ. Nacional Autónoma de México (Mexico)

11:40 AM

Optical design and optimization of Beam-Down CSP systems with secondary concentrators

Alan Giocoli, Aurelio Gonzalez-Pardo, Thorsten Denk, Plataforma Solar de Almería, Ctr. de Investigaciones Energéticas, Medioambientales y Tecnológicas (Spain)

Lunch Break 12:00 PM - 1:30 PM

Thermophotovoltaics and Solar Energy

1:30 PM

Storage integrated solar thermophotovoltaics: current developments and future prospects

Alejandro Datas, Esther López, Pablo García-Linares, Juan Villa, Alessandro Gallo, Myrto Zeneli, Univ. Politécnica de Madrid (Spain); Nicolas Loubet, Univ. Politécnica de Madrid (Spain), Thermophoton S.L. (Spain); Álvaro M. Medrano, Univ. Politécnica de Madrid (Spain); Daniel Milovich, Ignacio Izquierdo, Univ. Politécnica de Madrid (Spain), Thermophoton S.L. (Spain); Alicia López-Ceballos, Saad Akhtar, Univ. Politécnica de Madrid (Spain)

1:50 PM

Angular control for improved spectral filtering in thermophotovoltaics

Håkon Jarand Dugstad Johnsen, Norwegian Univ. of Science and Technology (Norway)

2:10 PM

AI-optimized tracking agrivoltaics

Peter Bermel, Geoff MacRae Sanchez, Changkyun Lee, Purdue Univ. (United States)

Coffee Break 2:30 PM - 3:00 PM

Radiative Cooling and Infrared Energy Conversion

3:00 PM

Greenhouse heat trapping control in enclosed spaces via Janus transparent radiative cooling

Junkyeong Park, Pohang Univ. of Science and Technology (Korea, Republic of); Hangyu Lim, Korea Univ. (Korea, Republic of); Harit Keawmuang, Pohang Univ. of Science and Technology (Korea, Republic of); Heon Lee, Korea Univ. (Korea, Republic of); Junsuk Rho, Pohang Univ. of Science and Technology (Korea, Republic of)

3:20 PM

AI-enabled inverse design of high-performance, durable, and scalable radiative cooling structures

Peter Bermel, Changkyun Lee, Purdue Univ. (United States)

3:40 PM

Intersubband photovoltaics for mid-infrared energy conversion

Debarati Sen, Eric J. Tervo, Univ. of Wisconsin-Madison (United States)

4:00 PM

Leveraging negative luminescence for thermoradiative energy conversion and communications

Michael P. Nielsen, Valerii Radchenkov, Nicholas J. Ekins-Daukes, The Univ. of New South Wales (Australia)

4:20 PM

Radiative cooling films for transparent windows

Seung Ah Yu, Kyung Hee Univ (Korea, Republic of); Seung Ah Yu, Jae Hyun Kim, Kyung Hee Univ. (Korea, Republic of)

Poster Session

5:30 PM

Characterization by ray tracing of the positioning of a parabolic reflector to optimize concentration in the Isthmus of Tehuantepec

Gabriel Castillo-Santiago, María-Fernanda Urbieta-Martínez, Univ. del Istmo (Mexico); Martín Jiménez-Rodríguez, Maximino A. Avendaño-Alejo, Univ. Nacional Autónoma de México (Mexico); Víctor Iván Moreno-Oliva, Edwin Román-Hernández, Univ. del Istmo (Mexico); Ismael Velázquez-Gómez, Osvaldo Ponce-Hernández, Univ. Nacional Autónoma de México (Mexico)

5:30 PM

Free-form SOE fabricated via 3D printing

Luis Alonso Altamirano-Barbosa, Ivan Salgado-Transito, Centro de Investigaciones en Óptica, A.C. (Mexico)

Tuesday, 25 August 2026

LED Optics and Additive Manufacturing

8:30 AM

Multi-LED illumination design benefitting spectroscopic sensing

Lien Smeesters, Dries Rosseel, Hugo Thienpont, Vrije Univ. Brussel (Belgium), Flanders Make (Belgium)

8:50 AM

Photobleaching of transparent photopolymer resins for use in LED lighting secondary optics

Charles Rhodes, Isabella Raisty, Jean Paul Freyssinier, Nadarajah Narendran, Rensselaer Polytechnic Institute (United States)

9:10 AM

3D printed non-imaging baffle-optics for linear LED light fixtures

Harithra Navaratnam, Nadarajah Narendran, Indika U. Perera, Rensselaer Polytechnic Institute (United States)

9:30 AM

Print parameter effect on thermal conductivity of 3D-printed component for LED system applications

Babajide Aremu, Indika U. Perera, Rensselaer Polytechnic Institute (United States)

Coffee Break 9:50 AM - 10:20 AM

Illumination Applications

10:20 AM

Backlighted public transport push-buttons: from photometric characterisation towards improved visual contrast

Lien Smeesters, Hugo Thienpont, Jürgen Van Erps, Vrije Univ. Brussel (Belgium), Flanders Make (Belgium)

10:40 AM

3D-printed tertiary optics to transform a circular beam of a reflector lamp into a square beam

Dineth Kottahachchi, Rensselaer Polytechnic Institute (United States); Kai-Di Peng, Tillotson Design Associates (United States); Harithra Navaratnam, Nadarajah Narendran, Indika U. Perera, Rensselaer Polytechnic Institute (United States)

11:00 AM

Comparison between aspherical concave Fresnel-type reflectors versus confocal parabolic mirrors for designing three-dimensional display systems

Maximino A. Avendaño-Alejo, Martín Jiménez-Rodríguez, Ismael Velázquez-Gómez, Osvaldo Ponce-Hernández, José Luis García-Rico, Univ. Nacional Autónoma de México (Mexico)

Nonimaging Optics Competition and Closing

11:20 AM

Nonimaging Optics Design Competition 2026: the square peg challenge

Håkon Jarand Dugstad Johnsen, Norwegian Univ. of Science and Technology (Norway); Lien Smeesters, Vrije Univ. Brussel (Belgium); Thomas A. Cooper, York Univ. (Canada)

11:40 AM

Conference Closing and Best Student and Postdoc Presentation Award Closing and awards

Håkon Jarand Dugstad Johnsen, Norwegian Univ. of Science and Technology (Norway); Lien Smeesters, Vrije Univ. Brussel (Belgium); Thomas A. Cooper, York Univ. (Canada)

Want to participate in this program?

Post-deadline abstracts are accepted through 29 June 2026. New submissions will be considered for the poster session, or for an oral session if space becomes available.

Submit post-deadline abstract