Optimal geometry for off-axis, freeform illumination design

Caleb Gannon, Rongguang Liang

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


A thorough investigation into the efficiency and performance of off-axis, freeform illumination systems has been conducted, and a method for arriving at the optimal tilt is established for both reflective and refractive designs. The optimal tilt for refractive designs is determined by minimizing the total light lost due to Fresnel reflections across the lens, while the optimal tilt for reflective designs ensures the source is not obstructing the reflected ray bundle. For uncoated lenses, utilizing the proposed tilt can improve efficiency by more than 150%.

Original languageEnglish (US)
Article number065102
JournalOptical Engineering
Issue number6
StatePublished - Jun 1 2018


  • freeform
  • illumination design
  • nonimaging optics

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • General Engineering


Dive into the research topics of 'Optimal geometry for off-axis, freeform illumination design'. Together they form a unique fingerprint.

Cite this