# Multi-element direct design using a freeform surface for a compact illumination system

> Research article (Applied Optics, 2017) · cited 16× · AI/ML

**Wikidata**: [openalex:W2767496479](https://www.wikidata.org/wiki/openalex:W2767496479)  
**Source**: https://4ort.xyz/entity/multi-element-direct-design-using-a-freeform-surface-for-a-compact-illumination-system