Progress Towards Alignment of Multi-Order Diffractive Engineered (MODE) Lens Segments using the Kinematically-Engaged Yoke System (KEYS) for Optical Performance Testing

Marcos A. Esparza, Ryan Luu, Heejoo Choi, Tom D. Milster, Daniel Apai, Daewook Kim

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Scopus citations


The continued development of multi-order diffractive engineered (MODE) lens technology that utilizes both multi-order diffractive surfaces and a diffractive Fresnel lens surface1–3 allows for the conception and development of future applications of the technology such as lightweight large aperture telescope primary lenses. Manufacturing methods being developed for this technology use glass compression molding to create its unique optical surface features. However, to enable the design and development of larger apertures using the MODE lens, it is necessary to allow segmentation due to the size constraints of current glass molding technology. Previous proceedings presented the effectiveness of the Kinematically-Engaged Yoke System (KEYS) to align the segments of a 0.24-m, PMMA, monochromatic, MODE-like lens (having no diffractive Fresnel lens features). The KEYS alignment system consists of ball bearings with which the step-like features of MODE lens segments kinematically engage with. In previous iterations of the KEYS, these ball bearings were mounted on ultra-fine screws that are adjusted radially with flexures that occupy space in the transverse plane (perpendicular to the MODE lens’s optical axis). We present a new iteration of KEYS in which these radially adjusting flexures have been modified to be located in planes that contain the MODE len’s optical axis. The alignment and optical performance of the MODE lens are evaluated using deflectometry in order to determine its current resolution of lens segment adjustment. Improvement of the KEYS will allow optical performance testing of the aligned lens. This version of KEYS will be used to assemble a 0.24-m, compression molded, glass, segmented MODE lens.

Original languageEnglish (US)
Title of host publicationOptical Manufacturing and Testing XIV
EditorsDaewook Kim, Heejoo Choi, Heidi Ottevaere, Rolf Rascher
ISBN (Electronic)9781510654266
StatePublished - 2022
EventOptical Manufacturing and Testing XIV 2022 - San Diego, United States
Duration: Aug 22 2022Aug 24 2022

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceOptical Manufacturing and Testing XIV 2022
Country/TerritoryUnited States
CitySan Diego


  • MODE lens
  • alignment
  • flexures
  • kinematic constraint
  • metrology
  • multi-segmented optics
  • optomechanics

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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