Accurate Single-Shot Phase Measurement Techniques for Optical Metrology

Accurate wavefront sensing is critical for multiple applications like freeform and aspheric optics for imaging and displays, space optics, biomedical optics, quantum photonic technologies, etc., as the demands for high-precision optical elements is ever increasing. In this webinar hosted by the Optical Metrology Technical Group, Prof. Kedar Khare will cover his work on single-shot phase measurement systems and algorithms that are important for optical metrology.

Off-the-shelf routine commercial array detectors (like CCD and CMOS) used in optical metrology systems are now sensitive enough to work at sub-millisecond frame exposures. Single-shot wavefront sensing systems using these detectors can therefore offer practical advantages, as the wavefront measurement can be performed without worrying about environmental mechanical vibrations. Getting full-resolution precision phase information from the single-shot intensity data requires new algorithmic ideas. In the context of interferometric systems, Prof. Khare shows that signal sparsity concepts can provide multipixel phase map recoveries with accuracy better than the standard shot noise limit even with classical light sources. In the context of non-interferometric systems, Prof. Khare describes the sampling advantage of the transport of intensity (TIE) phase retrieval approach that may provide an interesting solution to the high fringe density problem associated with interferometry of aspheric surfaces.

What You Will Learn:
• Role of wavefront sparsity in optical interferometry/metrology
• Single-pixel vs multi-pixel phase accuracy criteria
• Sampling advantage of transport of intensity phase measurement
• Iterative phase retrieval with vortex illumination

Who Should Attend:
• Masters students, Ph.D. students, and postdocs
• Professionals from both research and the manufacturing industry

About the Presenter: Kedar Khare from Indian Institute of Technology Delhi

Kedar Khare is a Professor at the Optics and Photonics Centre and Department of Physics, Indian Institute of Technology Delhi, New Delhi, India and additionally serves as the Editor-in-Chief for Journal of Modern Optics. He currently holds the Abdul Kalam Technology Innovation National Fellowship awarded by the Indian National Academy of Engineering. Prior to joining IIT Delhi, Dr. Khare spent over five years as a Lead Engineer/Scientist in the Imaging Technologies division of GE Global Research, Niskayuna, USA. Dr. Khare has made several contributions to the area of computational optical imaging, diagnostic healthcare imaging and structured light propagation in random media. Dr. Khare completed the integrated MSc course in Physics from Indian Institute of Technology Kharagpur (1999) and obtained a PhD in Optics from The Institute of Optics, University of Rochester, USA (2004).