Lensless imaging is an elegant approach to microscopy, in which a sharp image of an object is retrieved by numerical means rather than by actual optical components such as lenses. In lensless imaging, light that has interacted with an object (i.e. a diffraction pattern) is recorded directly, and an image of the object is retrieved through computer algorithms. The main challenge in lensless imaging is that this typically requires knowledge of the electric field of the detected light (both intensity and phase), while optical detectors only record intensity. Nevertheless, through controlled use of imaging conditions and the employed imaging geometry, even intensity-only measurements can allow for a numerical reconstruction of the full electric field of light. If the field is known, aberrations introduced by optical components and alignment imperfections can be mitigated numerically, leading to diffraction-limited high-quality images even when only simple optics, or even no optics at all, are used in the imaging system. The objective of this project is to advance this new technology towards high-impact applications, and to forge a coordinated research program on lensless imaging technology and its applications.
Within the frame of this project, we are developing novel methods that enable the construction of very simple yet highly powerful microscopes and imaging systems, which are not limited by the quality of the optical hardware. We are also working towards methods that allow for imaging through scattering and even optically opaque media, based on the same lensless imaging framework. Since the technology does not require precision optical components, we will be able to extend it to shorter wavelengths. We are working towards applications in EUV metrology and soft-X-ray imaging, such as ultra-high-resolution surface profiling of lithographic wafers. As such, this program provides exciting new prospects for fundamental science, industrial metrology and medical diagnostics alike.
