Stefan Witte

Biophotonics and Medical Imaging,

LaserLaB and Department of Physics, Vrije Universiteit Amsterdam

“Lensless microscopy: from X-ray imaging to miniature microscopes”

Lensless imaging is an elegant approach to microscopy, in which the image formation is achieved using computer algorithms rather than optical components. This has two major advantages, namely 1) it allows the development of extremely compact microscopes, since no optical components and lens systems are needed, and 2) it enables high-resolution imaging with radiation for which there are no good-quality imaging optics available, such as X-rays.

In lensless imaging, coherent light illuminates an object and the resulting diffraction pattern is recorded directly with an image sensor. A high-resolution image of the object can be retrieved if the electric field of the diffracted light is known. This is the main challenge in lensless imaging: since the sensor only measures light intensity, so that the phase information needs to be retrieved in other ways.

In this talk I will explain the principles of lensless imaging. I will discuss our efforts to develop an ultra-high-resolution soft-X-ray microscope for bio-imaging applications [1], as well as our recent results on the development of miniaturized phase contrast microscopes for live cell imaging [2].

[1] S. Witte, V.T. Tenner, D.W.E. Noom, K.S.E. Eikema, ArXiv:1302.6064 (2013).

[2] D.W.E. Noom, K.S.E. Eikema, S. Witte, Opt. Lett. 39, 193-196 (2014).

Friday 28 February 2014,

16.00h – 17.00h (drinks afterwards)

Oort Building, De Sitterzaal