ELOS 2021

Andriy Shevchenko

Andriy Shevchenko, Speaker at Andriy Shevchenko: Speaker for Optics Conference
Aalto University, Finland
Title : Aberration-insensitive interferometric microscopy

Abstract:

Imaging techniques based on optical correlation measurements and using spatially incoherent illumination have been shown to be able to reduce the effect of optical aberrations. One of such techniques is classical ghost imaging based on spatial intensity correlations in two optical beams of which one is transmitted through the object. The image can be obtained from the correlation measurements even though the object beam is analyzed with a bucket detector. Another imaging technique using spatially incoherent illumination is full-field optical coherence tomography that is based on optical interference instead of intensity correlations for three-dimensional imaging of back-scattering objects. This technique, utilizing light with short coherence time, is insensitive to aberrations if the wavefront shifts are smaller than the longitudinal coherence length of the field.

In this presentation, a novel interferometric ghost-like imaging microscopy that is insensitive to severe optical aberrations will be discussed. The aberration insensitivity stems from a large longitudinal coherence length of the applied spatially incoherent illumination. The approach makes use of a Mach-Zehnder interferometer for transmissive objects or a Michelson interferometer for reflective and back-scattering objects. The technique yields sharp and non-deformed microscope images even if the objects are screened by an optical diffuser that destroys the intensity image completely. Furthermore, not only amplitude, but also phase objects can be imaged with high resolution in the presence of strong aberrations. The resolution is given by the size of the aberration-free diffraction-limited point-spread function no matter if the aberrations are deterministic or random. The approach may find applications in optical microscopy and interferometry.

Biography:

Dr. Andriy Shevchenko is a finnish physicist. He received his D.Sc. (Tech.) degree from Helsinki University of Technology in 2004. In 2007, he was appointed as Docent in optical physics, and since 2012, he holds the position of University Lecturer at Aalto University, Finland. He is the author of more than 100 scientific publications in international journals and conference proceedings. He acted as a member of academic committees for scientific conferences, as an evaluator of scientific proposals and activities, e.g., for ERC Advanced Grant, and as a referee for many scientific journals. He currently acts as a Topical Editor for Optics Letters.

Watsapp