ERC FUNDED PROJECTS

I propose to pursue two emerging Force Microscopy techniques that allow measuring structural properties below the surface of the specimen. Whereas Force Microscopy (most commonly known under the name AFM) is usually limited to measuring the surface topography and surface properties of a specimen, I will demonstrate that Force Microscopy can achieve true 3D images of the structure of the cell nucleus. In Ultrasound Force Microscopy, an ultrasound wave is launched from below towards the surface of the specimen. After the sound waves interact with structures beneath the surface of the specimen, the local variations in the amplitude and phase shift of the ultrasonic surface motion is collected by the Force Microscopy tip. Previously, measured 2D maps of the surface response have shown that the surface response is sensitive to structures below the surface. In this project I will employ miniature AFM cantilevers and nanotube tips that I have already developed in my lab. This will allow me to quickly acquire many such 2D maps at a much wider range of ultrasound frequencies and from these 2D maps calculate the full 3D structure below the surface. I expect this technique to have a resolving power better than 10 nm in three dimensions as far as 2 microns below the surface. In parallel I will introduce a major improvement to a technique based on Nuclear Magnetic Resonance (NMR). Magnetic Resonance Force Microscopy measures the interaction of a rotating nuclear spin in the field gradient of a magnetic Force Microscopy tip. However, these forces are so small that they pose an enormous challenge. Miniature cantilevers and nanotube tips, in combination with additional innovations in the detection of the cantilever motion, can overcome this problem. I expect to be able to measure the combined signal of 100 proton spins or fewer, which will allow me to measure proton densities with a resolution of 5 nm, but possibly even with atomic resolution.

1 794 960 €

Start date: 2008-08-01, End date: 2013-07-31

The Tera-Hertz portion of the spectrum presents unique potentials for advanced applications. Currently the THz spectrum is revealing the mechanisms at the origin of our universe and provides the means to monitor the health of our planet via satellite based sensing of critical gases. Potentially time domain sensing of the THz spectrum will be the ideal tool for a vast variety of medical and security applications. Presently, systems in the THz regime are extremely expensive and consequently the THz spectrum is still the domain of only niche (expensive) scientific applications. The main problems are the lack of power and sensitivity. The wide unused THz spectral bandwidth is, herself, the only widely available resource that in the future can compensate for these problems. But, so far, when scientists try to really use the bandwidth, they run into an insurmountable physical limit: antenna dispersion. Antenna dispersion modifies the signal’s spectrum in a wavelength dependent manner in all types of radiation, but is particularly deleterious to THz signals because the spectrum is too wide and with foreseeable technology it cannot be digitized. The goal of this proposal is to introduce break-through antenna technology that will eliminate the dispersion bottle neck and revolutionize Time Domain sensing and Spectroscopic Space Science. Achieving these goals the project will pole vault THz imaging technology into the 21-th century and develop critically important enabling technologies which will satisfy the electrical engineering needs of the next 30 years and in the long run will enable multi Tera-bit wireless communications. In order to achieve these goals, I will first build upon two major breakthrough radiation mechanisms that I pioneered: Leaky Lenses and Connected Arrays. Eventually, ultra wide band imaging arrays constituted by thousands of components will be designed on the bases of the new theoretical findings and demonstrated.

1 499 487 €

Start date: 2011-11-01, End date: 2017-10-31

The emergence of coherent behaviour is ubiquitous in the natural world and has long captivated biologists and physicists alike. One area of growing interest is the collective motion and synchronization arising within and between simple motile organisms. My goal is to develop and use a novel experimental approach to unravel the origins of spontaneous coherent motion in three model systems of biofluids: (1) the synchronization of the two flagella of green algae Chlamydomonas Rheinhardtii, (2) the metachronal wave in the cilia of protist Paramecium and (3) the collective motion of swimming microorganisms in active suspensions. Understanding the mechanisms leading to collective motion is of tremendous importance because it is crucial to many biological processes such as mechanical signal transduction, embryonic development and biofilm formation. Up till now, most of the work has been theoretical and has led to the dominant view that hydrodynamic interactions are the main driving force for synchronization and collective motion. Recent experiments have challenged this view and highlighted the importance of direct mechanical contact. New experimental studies are now crucially needed. The state-of-the-art of experimental approaches consists of observations of unperturbed cells. The key innovation in our approach is to dynamically interact with microorganisms in real-time, at the relevant time and length scales. I will investigate the origins of coherent motion by reproducing synthetically the mechanical signatures of physiological flows and direct mechanical interactions and track precisely the response of the organism to the perturbations. Our new approach will incorporate optical tweezers to interact with motile cells, and a unique μ-Tomographic PIV setup to track their 3D micron-scale motion. This proposal tackles a timely question in biophysics and will yield new insight into the fundamental principles underlying collective motion in active biological matter.

1 500 000 €

Start date: 2017-04-01, End date: 2022-03-31

The discoveries that the expansion of the universe is accelerating due to an unknown “dark energy” and that most of the matter is invisible, highlight our lack of understanding of the major constituents of the universe. These surprising findings set the stage for research in cosmology at the start of the 21st century. The objective of this proposal is to advance observational constraints to a level where we can distinguish between physical mechanisms that aim to explain the properties of dark energy and the observed distribution of dark matter throughout the universe. We use a relatively new technique called weak gravitational lensing: the accurate measurement of correlations in the orientations of distant galaxies enables us to map the dark matter distribution directly and to extract the cosmological information that is encoded by the large-scale structure. To study the dark universe we will analyse data from a new state-of-the-art imaging survey: the Kilo- Degree Survey (KiDS) will cover 1500 square degrees in 9 filters. The combination of its large survey area and the availability of exquisite photometric redshifts for the sources makes KiDS the first project that can place interesting constraints on the dark energy equation-of-state using lensing data alone. Combined with complementary results from Planck, our measurements will provide one of the best views of the dark side of the universe before much larger space-based projects commence. To reach the desired accuracy we need to carefully measure the shapes of distant background galaxies. We also need to account for any intrinsic alignments that arise due to tidal interactions, rather than through lensing. Reducing these observational and physical biases to negligible levels is a necessarystep to ensure the success of KiDS and an important part of our preparation for more challenging projects such as the European-led space mission Euclid.

1 316 880 €

Start date: 2012-01-01, End date: 2016-12-31