Publications de Marcel Leutenegger

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Super-resolution optical fluctuation imaging (SOFI) provides an elegant way of overcoming the diffraction limit in all three spatial dimensions by computing higher-order cumulants of image sequences of blinking fluorophores acquired with a classical widefi ...

We report on the fabrication of two-dimensional arrays of nano-optical apertures in gold layers by electron beam lithography (EBL) on a transparent glass substrate. 30 x 30 μ m(2) large arrays of high aspect ratio sub-wavelength cylinders (400 nm diameter ...

In this paper we describe the fabrication of a two-dimensional photonic band gap structure by focused electron beam induced deposition. Structure geometry is computed in order to create a light-trapping effect at 632 nm wavelength. Deposits produced using tetraethyl orthosilicate (SiO4C8H20) as precursor were studied to determine their chemical composition and geometrical dimensions. The deposited material has a refractive index ~n ¼ 1:85 þ i3:9 � 10�4 at 632 nm. Transmission electron microscopy revealed

During open brain surgery we acquire perfusion images non-invasively using laser Doppler imaging. The regions of brain activity show a distinct signal in response to stimulation providing intraoperative functional brain maps of remarkably strong contrast. ...

Triplet imaging is a novel optical technique that allows investigating oxy- gen metabolism at the single cell and the sub-cellular level. The method combines high temporal and spatial resolution, which are required for the monitoring of fast kinetics of ox ...

The present invention relates to a functional optical coherent imaging (fOCI) platform comprising at least one active camera unit (ACU) comprising a coherent and/or a partially coherent light source, and means for spectral filtering and imaging a selected ...

We present a fast calculation of the electromagnetic field near the focus of an objective with a high numerical aperture (NA). Instead of direct integration, the vectorial Debye diffraction integral is evaluated with the fast Fourier transform for calculat ...

Super-resolution optical fluctuation imaging (SOFI) achieves 3D super-resolution by computing temporal cumulants or spatio-temporal cross-cumulants of stochastically blinking fluorophores. In contrast to localization microscopy, SOFI is compatible with wea ...

Diffraction-unlimited fluorescence imaging allows the visualization of intact, strongly heterogeneous systems at unprecedented levels of detail. Beyond the acquisition of detailed pictures, increasing efforts are now being focused on deriving quantitative ...

Super-resolution optical fluctuation imaging (SOFI) allows one to perform sub-diffraction fluorescence microscopy of living cells. By analyzing the acquired image sequence with an advanced correlation method, i.e. a high-order cross-cumulant analysis, super-resolution in all three spatial dimensions can be achieved. Here we introduce a software tool for a simple qualitative comparison of SOFI images under simulated conditions considering parameters of the microscope setup and essential properties of the bio

A novel imaging method employing the different kinetics of the energetic states of fluorescent markers is presented, where the contrast depends on the triplet kinetics. An attractive feature of triplet states is their long lifetime, rendering them highly sensitive to the immediate environment of their fluorescent host molecules. They typically have a lifetime of the order of ~10us to 10ms, which is 3-6 orders of magnitude longer than the lifetimes of fluorescent singlet states. The concept exploits characte

Fluorescence fluctuation spectroscopy based on an evanescent field excitation scheme leads to an alternative concept for single molecule detection with interesting experimental features. This concept is described and analyzed regarding the total fluorescence process including excitation, fluorescence emission and collection close to a dielectric interface. The realized experimental scheme showed superior performance of this concept with substantially enhanced molecular brightness when compared to the classi

We address the problem of high-resolution reconstruction in frequency-domain optical-coherence tomography (FDOCT). The traditional method employed uses the inverse discrete Fourier transform, which is limited in resolution due to the Heisenberg uncertainty ...

The identification and accurate location of centers of brain activity are vital both in neuro-surgery and brain research. This study aimed to provide a non-invasive, non-contact, accurate, rapid and user-friendly means of producing functional images intrao ...

Fourier Domain Optical Coherence Tomography (FDOCT) is a high speed biomedical imaging modality which extracts the sample structure in depth. The axial resolution is given by the coherence length of the employed light source. The lateral resolution on the other hand is determined by the numerical aperture (NA) of the objective. The parallel detection of the depth information has the drawback of loosing transverse resolution along the optical axis, limiting the depth of field (DOF) and the use of FDOCT in th

We present the results on two-photon total-internal-reflection fluorescence correlation spectroscopy. The combination of liquid crystal spatial light modulator, providing radial polarization, with ultrafast laser (picosecond Nd:GdVO4 laser) allowed us to take the advantage of nonlinear optical contrast mechanisms to suppress the side-lobe energy specific for radial polarization and reduce the effective excited volume twice compared to one-photon evanescent wave excitation in fluorescence correlation spectro

We developed a dual-color total internal reflection fluorescence (TIRF) system for single molecule imaging and fluorescence fluctuation spectroscopy (FFS). For a performance analysis, we measured a synthetic binding assay with dual-color global fluorescence correlation spectroscopy (2CG-FCS) and dual-color fluorescence intensity distribution analysis (2D-FIDA). We show that dual-color TIR-FFS is a suitable method for measuring coincidence assays at the surface. In particular, our setup has a very high fluor

We present a novel concept for optical spectroscopy called nonlinear correlation spectroscopy (NLCS). NLCS analyses coherent field fluctuations of the second and third harmonic light generated by diffusing nanoparticles. Particles based on noncentrosymmetr ...

Optical prism comprising two external parallel and reflecting surfaces, one internal interface, parallel to said surfaces and acting as light splitter; said prism furthermore comprising an entrance side forming an angle β with respect to said interface and ...

Marcel Leutenegger

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Live-cell multiplane three-dimensional super-resolution optical fluctuation imaging

Fabrication of arrays of sub-wavelength nano-apertures in an optically thick gold layer on glass slides for optical studies

Focused electron beam induced deposition of a periodic transparent nano-optic pattern

See the Brain at Work—Intraoperative Laser Doppler Functional Brain Imaging

Triplet imaging of oxygen consumption during the contraction of a single smooth muscle cell (A7r5)

Functional optical coherent imaging platform for medical application e.g. neurosurgery, has active camera unit that captures image of specific region of test subject after transmitting stimulus signals

Fast focus field calculations

Mapping molecular statistics with balanced super-resolution optical fluctuation imaging (bSOFI)

Diffraction-unlimited imaging: from pretty pictures to hard numbers

SOFI Simulation Tool: A Software Package for Simulating and Testing Super-Resolution Optical Fluctuation Imaging

Triplet imaging contrast by modulated excitation

Single molecule detection at surfaces

Zero-crossing approach to high-resolution reconstruction in frequency-domain optical-coherence tomography

Laser Doppler imaging for intraoperative human brain mapping

Fourier Domain Optical Coherence Microscopy with Extended Depth of Field

High volume confinement in two-photon fluorescence correlation spectroscopy with radially polarized light

Dual-color Total Internal Reflection Fluorescence Fluctuation Spectroscopy

Dual-color Total Internal Reflection Fluorescence Fluctuation Spectroscopy

Nonlinear Correlation Spectroscopy (NLCS)

Optical prism for creating multiple views of an image