Publications by Theo Lasser | EPFL Graph Search

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Diode-pumped solid body laser comprises an acoustic-optical modulator, a laser crystal, a delay plate and a crystal that doubles the frequency of the laser beam. Pulse lengthening is carried out by internal coupling of a doubler mechanism within the laser resonator Preferred Features: The end surface of the laser crystal is formed as an end mirror limiting the laser resonator. The mirror is highly reflective for the laser beam. Crystals of SiO2 or TeO2 are provided for the acoustic-optical modulator.

Extended focus optical coherence microscope (xfOCM) circumvents the compromise between lateral resolution and depth of field by us of a Bessel-like illumination beam. The high sensitivity and parallel depth profiling of Fourier domain optical coherence tomography are preserved, and combined with high isotropic resolution of 1.5 - 2 μm. To comply with the requirements for in vivo measurements, beam scanning had to be implemented. We then performed measurements, first of excised pancreas, validated by standar

We report on a new detection scheme for Fourier domain optical coherence microscopy that exhibits high transverse resolution along an axially extended focal range. Nearly constant transverse resolution of ∼1.5 μm along a focal range of 200 μm is experiment ...

We demonstrate nanometer-level localization accuracy of a single fluorescent emitter in three dimensions. Our super resolution microscopy technique is based on spectral self-interference for axial localization and two-dimensional diffraction pattern analysis for lateral localization.

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 ...

We present a full field laser Doppler imaging instrument, which enables real-time in vivo assessment of blood flow in dermal tissue and skin. This instrument monitors the blood perfusion in an area of about 50 cm² with 480 × 480 pixels per frame at a rate ...

We achieved photon count rates per molecule as high as with commonly used confocal fluorescence correlation spectroscopy instruments using a new total internal reflection fluorescence correlation spectroscopy system based on an epi-illumination configurati ...

For the observation of single molecule dynamics with fluorescence fluctuation spectroscopy (FFS) very low fluorophore concentrations are necessary. For in vitro measurements, this requirement is easy to fulfill. In biology however, micromolar concentration ...

We introduce photothermal optical lock-in Optical Coherence Microscopy (poli-OCM), a volumetric imaging technique, which combines the depth sectioning of OCM with the high sensitivity of photothermal microscopy while maintaining the fast acquisition speed ...

NOVELTY - The method involves illuminating a field (11) of brain (13) of a patient for acquiring an image sequence of the field. The field is illuminated after stimulating the patient for acquiring another image sequence. The image sequences are evaluated ...

We show nanometer-level localization accuracy of a single quantum-dot in three dimensions by self-interference and diffraction-pattern analysis. We believe that this approach has the capacity to push optical microscopy to the molecular level.

Nanoparticles are interesting for biomedical imaging as novel non- fluorescent non-bleaching labels. We present the characterization of freely diffusing nanoparticles using third harmonic generation correlation spectroscopy by illumination with a focussed pulsed femtosecond laser. We present the optical system as well as first spectroscopic results on nanoparticles.

We present a novel extended-focus optical coherence microscope (OCM) attaining 0.7 μm axial and 0.4 μm lateral resolution maintained over a depth of 40 μm, while preserving the advantages of Fourier domain OCM. Our system uses an ultra-broad spectrum from ...

Most current optical coherence tomography systems provide two-dimensional cross-sectional or en face images. Successive adjacent images have to be acquired to reconstruct three-dimensional objects, which can be time consuming. Here we demonstrate three-dimensional optical coherence tomography (3D OCT) at video rate. A 58 by 58 smart-pixel detector array was employed. A sample volume of 210x210x80 mum(3) (corresponding to 58x58x58 voxels) was imaged at 25 Hz. The longitudinal and transverse resolutions are 3

We present a comprehensive study of multiple-scattering effects in wide-field optical coherence tomography (OCT) realized with spatially coherent illumination. Imaging a sample made of a cleaved mirror embedded in an aqueous suspension of microspheres reve ...

A method and system for the rapid detection of biomolecular interactions, the system comprising a sensing platform which comprises a primary support structure including recesses designed to be located in front of a detection unit, said recesses containing ...

We present a new concept for fluorescence lifetime imaging (FLIM) based on time-resolved Hadamard imaging (HI). HI allows image acquisition by use of one single-point detector without requiring a moving scanning stage. Moreover, it reduces the influence of ...

Interferometric imaging techniques typically embed the object phase information in the magnitude during the measurement process. During reconstruction, the phase is recovered from the magnitude by certain approximations on the measured magnitude and underl ...

Theo Lasser

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Diode-pumped solid body laser used in ophthalmology comprises an acoustic-optical modulator, a laser crystal, a delay plate and a crystal that doubles the frequency of the laser beam

In vivo imaging of pancreatic endocrine islets

Extended focus depth for Fourier domain optical coherence microscopy

Three-dimensional Localization of Fluorescent Emitters at the Nano-scale

Optical prism for creating multiple views of an image

Real-time full field laser Doppler imaging

High count rates with total internal reflection fluorescence correlation spectroscopy

Confining the sampling volume for Fluorescence Correlation Spectroscopy using a sub-wavelength sized aperture

Fast three-dimensional imaging of gold nanoparticles in living cells with photothermal optical lock-in Optical Coherence Microscopy

Method for displaying field e.g. tumor, of brain of human patient during surgery of brain, involves acquiring topography data representing topography of field, where output image is displayed based on topography data

Three-Dimensional Localization of Nano-Emitters with Nanometer-Level Precision

Characterization of Nanoparticles Using Non-linear Correlation Spectroscopy

Three dimensional time lapse imaging of live cell mitochondria with photothermal optical lock-in optical coherence microscopy (Conference Presentation)

Three-Dimensional Localization of Nano-Emitters with Nanometer-Level Precision

Visible spectrum extended-focus optical coherence microscopy for label-free sub-cellular tomography

Video-rate three-dimensional optical coherence tomography

Multiple scattering in optical coherence tomography. II. Experimental and theoretical investigation of cross talk in wide-field optical coherence tomography

Apparatus and method for detecting and measuring biomolecular interactions

Time-resolved Hadamard fluorescence imaging

HILBERT TRANSFORM RELATIONS IN FREQUENCY-DOMAIN OPTICAL-COHERENCE TOMOGRAPHIC IMAGING