Structured illumination assisted microdeflectometry with optical depth scanning capability

Sheng Huei Lu, Hong Hua

Research output: Contribution to journalArticle

5 Scopus citations

Abstract

Microdeflectometry is a powerful noncontact tool for measuring nanometer defects on a freeform surface. However, it requires a time-consuming process to take measurements at different depths for an extended depth of field (EDOF) and lacks surface information for integrating the measured gradient data to height. We propose an optical depth scanning technique to speed up the measurement process and introduce the structured illumination technique to efficiently determine the focused data among 3D observation and provide surface orientations for reconstructing an unknown surface shape. We demonstrated 3D measurements with an equivalent surface height sensitivity of 7.21 nm and an EDOF of at least 250 μm, which is 15 times that of the diffraction limited depth range.

Original languageEnglish (US)
Pages (from-to)4114-4117
Number of pages4
JournalOptics Letters
Volume41
Issue number17
DOIs
StatePublished - Sep 1 2016

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

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