Group Leader


Optimizing light-sculpting microscopy for neuroscience

BioMedOptExp_website_fig_forRobertYesterday our most recent paper got published in Biomedical Optics Express. Our article, entitled “Optimizing and extending light-sculpting microscopy for fast functional imaging in neuroscience” studies various experimental trade-offs in temporal focusing based light-sculpting microscopy and shows how to optimize its performance based on specific experimental requirements. Furthermore, we show that synchronization of line-scanning techniques with rolling-shutter read-out of the scientific camera can reduce scattering effects and thus enhance image contrast at depth. Our theoretical and experimental results were corroborated by performing calcium-imaging of acute mouse brain slices expressing the calcium reporter GCaMP6m. In contrast to our previous work using wide-field TeFo, we were able to significantly increase the imaging field-of-view while maintaining physiologically relevant imaging speeds, even in the cases where a standard Ti:Sa laser was employed. We hope that these results will make light-sculpting a more practical and thus widely applicable imaging technique in the life sciences and neuroscience in particular.


LFDM makes the cover of Nature Methods

Great news! Nature Methods has selected our artwork on light-field deconvolution microscopy as their July cover. Check out the cover image below and read about it online here!


Interview on

My colleague, Tina Schrödel, as well as myself have recently been interviewed about our research by a Dutch film crew. They’re running a cool video blog and online platform on cutting-edge research in the nanosciences,, funded by the European Union. We were both proud to be selected for the interview, although our brain-wide 3D imaging methods in C. elegans using wide-field temporal focusing microscopy can probably not be considered ‘nano’. The idea of the video clips is to ask a question to another fellow researcher in Europe who then in turn gets interviewed. Watch our video clip below!

Light-field microscopy of whole animals

zebrafish_coloredTwo weeks ago, our most recent paper got published online in Nature Methods. The paper is entitled “Simultaneous whole-animal 3D imaging of neuronal activity using light-field microscopy“.

In this paper, we establish light-field microscopy as a method to capture neuronal dynamics of both C. elegans and zebrafish larvae. Applying 3D-deconvolution in post-processing allows us to aimage large volumes while retaining single-neuron resolution. This research was a collaborative effort between our lab and the group of Ed Boyden at the MIT Media Lab. Read the abstract of our article below:

High-speed, large-scale three-dimensional (3D) imaging of neuronal activity poses a major challenge in neuroscience. Here we demonstrate simultaneous functional imaging of neuronal activity at single-neuron resolution in an entire Caenorhabditis elegans and in larval zebrafish brain. Our technique captures the dynamics of spiking neurons in volumes of ~700 μm × 700 μm × 200 μm at 20 Hz. Its simplicity makes it an attractive tool for high-speed volumetric calcium imaging.

The IMP and MFPL communication teams wrote nice press releases, which you can find here in German and English. The publication was picked up by several news outlets, most notably by a mentioning in an article by The Economist.

UPDATE: We’ve also made it into Nature News. Read the article about our paper here.
UPDATE#2: An interview of myself was published online by Novus Light Technologies Today here.

Also, we’ve made the cover of the July issue!! See post above.

Long-distance violation of Mermin’s inequality

NatPhoton_spacetimeYesterday our paper entitled ‘Experimental three-photon quantum nonlocality under strict locality conditions‘ was published advanced online in Nature Photonics. Here the link to the paper and abstract:

Quantum correlations, often observed as violations of Bell inequalities, are critical to our understanding of the quantum world, with far-reaching technological and fundamental impact. Many tests of Bell inequalities have studied pairs of correlated particles. However, interest in multi-particle quantum correlations is driving the experimental frontier to test larger systems. All violations to date require supplementary assumptions that open results to loopholes, the closing of which is one of the most important challenges in quantum science. Seminal experiments have closed some loopholes, but no experiment has closed locality loopholes with three or more particles. Here, we close both the locality and freedom-of-choice loopholes by distributing three-photon Greenberger–Horne–Zeilinger entangled states to independent observers. We measured a violation of Mermin’s inequality with parameter 2.77 ± 0.08, violating its classical bound by nine standard deviations. These results are a milestone in multi-party quantum communication and a significant advancement of the foundations of quantum mechanics.

Congrats to Chris Erven and the whole team for pulling off such a beautiful experiment!

UPDATE: Geoff Pryde has written an interesting News & Views in Nature Photonics on our experiment. Access it here.

IMP annual report feature

The research institute I work at (the IMP) publishes an annual report, in which each year the accomplishments of two researchers are highlighted and featured in a two-page essay. Following the success and positive feedback of our recent light-sculpting paper (see here), this year the IMP chose Tina’s and my work to be featured. You can read the story about our experiments here, or download the entire annual report by clicking on this link.


‘Quantum Computing on encrypted data’ appears in Nature Communications

Our paper entitled “Quantum Computing on encrypted data” was published recently in Nature Communications. You can read the abstract below and access the manuscript here. Congratulations to the main authors, Kent and Anne. Well done!

Abstract: The ability to perform computations on encrypted data is a powerful tool for protecting privacy. Recently, protocols to achieve this on classical computing systems have been found. Here, we present an efficient solution to the quantum analogue of this problem that enables arbitrary quantum computations to be carried out on encrypted quantum data. We prove that an untrusted server can implement a universal set of quantum gates on encrypted quantum bits (qubits) without learning any information about the inputs, while the client, knowing the decryption key, can easily decrypt the results of the computation. We experimentally demonstrate, using single photons and linear optics, the encryption and decryption scheme on a set of gates sufficient for arbitrary quantum computations. As our protocol requires few extra resources compared with other schemes it can be easily incorporated into the design of future quantum servers. These results will play a key role in enabling the development of secure distributed quantum systems.