Diffractive infrared lens with extended depth of focus

Zhiqiang Liu, Angel Flores, Michael R. Wang, Jame J. Yang

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


An infrared imaging lens that produces beams with long focal depth while preserving the entire aperture for full light capturing and high transverse resolution is presented. Based on the conjugate-gradient algorithm, a diffractive optical lens with four times depth of focus improvement at the 10.6-μm wavelength has been designed and fabricated. ZEMAX simulation has confirmed the designed lens performance showing legible images over an extended image range. Through laser direct-write photoresist patterning and subsequent reactive ion etching on a germanium substrate, we have realized a diffractive lens with four times depth of focus improvement over a conventional infrared lens of the same numerical aperture. The extended depth of focus lens should yield a variety of applications in focus-free imaging without reducing lens aperture.

Original languageEnglish (US)
Article number018002
JournalOptical Engineering
Issue number1
StatePublished - Jan 2007


  • Diffractive optics
  • Extended depth of focus
  • Infrared imaging

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics


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