Project Details
Projekt
Digital Holographic Microscope
Subject Area
Systems Engineering
Term
Funded in 2023
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 533907333
With digital holographic microscopy (DHM), micro- and nanostructures can be characterized in 4D, i.e. time- and space-resolved. The method is based on the recording of phase interference images, which are generated by superimposing a reference laser beam with a beam from the same source penetrating the sample. In contrast to other microscopy methods, DHM is characterized by the fact that it is not the projected image of the object that is recorded, but a digital hologram from which an object image can be reconstructed. This approach allows both a precise imaging of complex structures with nanometer resolution and the analysis of dynamic processes such as vibrations with frequencies up to the MHz range. Such microscopes can be operated in reflection and transmission configurations and enable the examination of a wide range of different samples from MEMS/NEMS systems to biological cell structures. The main areas of research for which the DHM in this proposal will be used include the characterization of micro- and nano-cantilevers, which are integrated in a new co-resonant sensor concept, dynamic optomechanical systems with applications as gravitational lenses and photonic crystals, as well as dynamic surface changes of smart polymers in a sensor context. The common denominator for all of these applications is that they feature complex three-dimensional surface topographies down to the nanometer scale and require an analysis of their static (e.g. topography, deformations) and in particular their dynamic behavior (e.g. vibrations). Due to the small dimensions of the structures and systems to be investigated, frequency and time resolutions down to the megahertz / microsecond range are required in the latter case. In the case of cantilever sensors in particular very large vibration amplitudes, which can easily exceed several times the beam’s thickness, are of interest for studying energy distributions and non-linear effects. In the case of smart polymers, a major challenge are their usually very soft surfaces which significantly limits the use of contact methods such as scanning probe microscopy. Digital holographic microscopy is a non-contact method that can meet all of these requirements and is therefore a crucial tool in conducting research in the described topics.
DFG Programme
Major Research Instrumentation
Major Instrumentation
Digitales Holographie Mikroskop
Instrumentation Group
5310 Interferenzapparaturen, Zweistrahl-Interferometer
Applicant Institution
Gottfried Wilhelm Leibniz Universität Hannover
