Design Competition - Frequently Asked Questions

What is Nonimaging Optics?

Nonimaging optics is a field that focuses on the optimal transfer of light energy rather than forming images. Unlike traditional optics that aims to create clear images (like camera lenses, microscopes, or telescopes), nonimaging optics is concerned with efficiently collecting, concentrating, or distributing light energy. This is particularly relevant for applications like solar energy or illumination systems.

Below are some good introductory resources if you want to learn more:

Nonimaging Optics: A Tutorial - An open-access article giving an overview of some fundamental methods and concepts
Nonimaging Optics by Roland Winston, Juan C. Miñano, and Pablo Benítez - A classic reference covering the theoretical foundations
Introduction to Nonimaging Optics by Julio Chaves - A comprehensive textbook on the field
Illumination Engineering: Design with Nonimaging Optics by R. John Koshel - Focused on illumination applications
Designing Illumination Optics by Julius A. Muschaweck, Henning Rehn - A practical guide to designing illumination systems, including principles of nonimaging optics

I come from another research field, can I still try?

We absolutely welcome this! As an outsider you might bring new ideas into the field. Maybe you even want to submit an abstract to the conference based on your outsider-approach to solving the competition challenge?

Feel free to email us if anything about the competition rules are unclear to you.

What does it mean that the étendue is matched?

Étendue can be seen as the “volume” of light in phase space, encompassing both the spatial and angular spread of the light. A passive optical system can reshape this étendue, but conservation of étendue means that we cannot shrink the étendue in a passive optical system without losing energy. In this optical design problem, the source and target have equal étendue, meaning that the light from the source exactly “fits” into the target. The question is then how to design an optical system that can achieve this perfect transfer of light.

The source consists of 6 square faces of side length $L = 45 \text{ mm}$ . The emission from each face covers a hemisphere minus a blocked central cone of half-angle $\theta = 66.30^\circ$ . The projected solid angle is therefore $\pi(1 - \sin^2\theta)$ .

U_{source} = 6 \cdot L^2 \cdot \pi (1 - \sin^2 \theta) = 6 \cdot (45 \text{ mm})^2 \cdot \pi (1 - \sin^2 66.30^\circ) \approx 6170 \text{ mm}^2\text{sr}

The target is a circular aperture of radius $r = 25 \text{ mm}$ . It accepts light from the full hemisphere, corresponding to a projected solid angle of $\pi$ .

U_{target} = (\pi r^2) \cdot \pi = \pi^2 \cdot (25 \text{ mm})^2 \approx 6170\text{ mm}^2\text{sr}

How is the efficiency calculated?

The efficiency is calculated by ray tracing in our submission portal. We generate rays following the special angular distribution and uniform spatial distribution of the emissive cube. The efficiency is the fraction of these rays that reach the target disc, taking into account the 95% reflectivity of the mirrors.

How is the upload portal made?

The Nonimaging Optics Conference website is built using the static site generator Astro. The upload portal is built with the framework SolidJS, and integrated into the Astro site as a client-side reactive island. The 3D visualization is built using Three.js, with ray-tracing accelerated using Three-mesh-bvh. STEP import is implemented using OpenCascade.js.

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