The research in the nano-optics division aims to advance experimental and theoretical mastery of light-matter interaction at the nanometer scale. To do this, we combine concepts from quantum optics, laser spectroscopy, cryogenics, optical imaging, scanning probe technology and nanofluidics. The current two main areas of research are:
We have more than two decades of experience in the investigation of fundamental optical processes at the single photon and single emitter level. For example, we pioneered the demonstration of efficient coupling between light and a single quantum emitter without a need for cavities or antennas. We also demonstrated one of the very first and most quantitative cases of radiative enhancement by a plasmonic nanoantenna. Most of our work concerns solid-state samples and single organic molecules, but our findings are often generalizable to other systems such as atoms, ions, quantum dots, or color centers. The next generation of nano-quantum-optics research in our group will focus on the realization and investigation of a controlled number of interacting quantum emitters, photons and phonons.
Our efforts in this exciting area of research started in second half of the 2000s, where we showed that a single virus could be detected on a lipid membrane through interferometric scattering microscopy (iSCAT). This technique, which we first introduced in 2004, remains a central pillar of our nano-bio-photonics work. Indeed, iSCAT has now become a widespread and quantitative microscopy method in many laboratories around the world. For a review of iSCAT, please consult a recent minireview in Nano Letters or this book chapter. In addition to iSCAT, we have pioneered angstrom resolution in fluorescence microscopy via cryogenic measurements. Overall, our activities in nano-bio-photonics have two main directions: 1) development of novel measurement techniques, whereby we massively benefit from our know-how in experimental quantum optics, and 2) application of mathematical and experimental techniques to the detection, microscopy, tracking, and manipulation of biological nano-objects such as viruses and proteins. Here, we collaborate with many biologist, biophysicists, and medical researchers across the world. In fact, we have recently founded the Max-Planck-Zentrum für Physik und Medizin to foster this line of research.