Christian Depeursinge

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Endoluminal microscopy and spectroscopy could significantly improve the efficiency of clinical endoscopic examination by allowing in-situ detection, staging and grading of potentially cancerous lesions. Indeed, high-end optical microscopy techniques such a ...

Digital Holographic Microscopy (DHM) is a single shot interferometric technique, which provides quantitative phase images with subwavelength axial accuracy. A short hologram acquisition time (down to microseconds), allows DHM to offer a reduced sensitivity ...

Process engineering and failure analysis of MEMS and MOEMS require static and dynamical characterization of both their in-plane and out of plane response to an excitation. A remarkable characteristic of Digital Holography Microscopes (DHM) is the extremely short acquisition time required to grab the whole information necessary to provide 3D optical topography of the sample: a unique frame grab, without any vertical or lateral scan provides the information over the full field of view. First, it ensures DHM m

We present what we believe to be a new digital holographic imaging method that is able to determine simultaneously the distributions of intensity, phase, and polarization state at the surface of a specimen on the basis of a single image acquisition. Two reference waves with orthogonal polarization states interfere with the object wave to create a hologram that is recorded on a CCD camera. Two wave fronts, one for each perpendicular polarization state, are numerically reconstructed in intensity and phase. Co

Digital holographic Microscopy (DHM) is an imaging modality reconstructing the wavefront in a numerical form, directly from a single digitalized hologram. It brings quantitative data derived simultaneously from the amplitude and phase of the complex reconstructed wavefront diffracted by the object and it is used to determine the refractive index and/or shape of the object with accuracy in the nanometer range along the optical axis. DHM comprises a microscope objective to adapt the sampling capacity of the c

Previous investigations on mammalian cells have shown that microgravity, either that experienced in space, or simulated on earth, causes severe cellular modifications that compromise tissue determination and function. The aim of this study is to investigat ...

We describe an optimized digital holographic microscopy system (DHM) suitable for high-resolution visualization of living cells under conditions of altered macroscopic mechanical forces such as those that arise from changes in gravitational force. Experime ...

Digital holographic microscopy (DHM) has been gaining interest from cell biology community because of its label free nature and quantitative phase signal output. Besides, fast shutter time, image reconstruction by numerical propagation of the wave fields, and numerical compensation of the aberrations are other intrinsic advantages of this technique that can be explored for harsh imaging conditions. In the frame of this work, a transmission type DHM is developed with a decoupled epifluorescence microscopy mo

In digital holographic microscopy, shot noise is an intrinsic part of the recording process with a digital camera. We present a study based on simulations describing how shot noise influences the quality of the reconstructed phase images under different beams intensities configurations. A model for image quality estimation based on the decision statistical theory proposed by Wagner and Brown (R.F. Wagner and D.G. Brown, "Unified SNR Analysis of Medical Imaging-Systems," Phys. Med. Biol. 30, 489-518 (1985))

The use of numerical procedure at a level never reach so far in optical imaging enables DHM to overcome two cumbersome alignment procedures of interferometric microscopes: (1) fine focus of the sample, and (2) sample tilt adjustment. In addition the technology enables to retrieve the full information from a single hologram acquisition. This enables very short acquisition time, smaller than typical propagation frequencies of ambient vibrations. These instruments can be operated without vibration insulation t

Quantitative phase imaging (QPI) has emerged as a valuable method for investigating cells and tissues. QPI operates on unlabelled specimens and, as such, is complementary to established fluorescence microscopy, exhibiting lower phototoxicity and no photobl ...

We present a novel technique for three-dimensional (3D) image processing of complex fields. It consists in inverting the coherent image formation by filtering the complex spectrum with a realistic 3D coherent transfer function (CTF) of a high-NA digital ho ...

The coherent nature of second harmonic generation (SHG) makes possible retrieval of both its amplitude and its phase, by use of a proper phase-sensitive imaging technique such as digital holographic SHG microscopy. In addition to retrieving both amplitude and phase of second harmonic signals the computer-based hologram reconstruction process also makes possible to bring in focus different sections of a specimen separated by distances exceeding the depth of field of the imaging system. Similarly, its numeric

We report on new developments of a technique, called Digital Holographic Microscopy (DHM), for the numerical reconstruction of digital holograms taken in microscopy, which allows simultaneous amplitude and quantitative phase contrast imaging. The reconstruction method computes the propagation of the complex optical wavefront diffracted by the object and is used to determine the refractive index and/or shape of the object with accuracies in the nanometer range along the optical axis. The method requires the

We present two digital image processing methods for image quality enhancement in Digital Holographic Microscopy (DHM). With the first method, the Fourier transform of an off-axis hologram is spatially filtered in order to eliminate the zero order of diffraction and the twin image. We show that this operation enhances the image contrast and the signal to background ratio. The second method describes an original technique to perform the apodization of the hologram with a transmission profile which follows a c

Red blood cell (RBC) membrane fluctuations provide important insights into cell states. We present a spatial analysis of red blood cell membrane fluctuations by using digital holographic Microscopy (DHM). This interferometric and dye-free technique, posses ...

The present invention discloses a method to improve the image resolution of a microscope. This improvement is based on the mathematical processing of the complex field computed from the measurements with a microscope of the wave emitted or scattered by the ...

In digital holographic microscopy, shot noise is an intrinsic part of the recording process with the digital camera. We present a study based on simulations and real measurements describing the shot-noise influence in the quality of the reconstructed phase ...

A dual-wavelength digital holographic microscope to measure absolute volume of living cells is proposed. The optical setup allows us to reconstruct two quantitative phase contrast images at two different wavelengths from a single hologram acquisition. When ...

The object of this work has been to develop a mechanical and numerical model of the eye submitted to vibrations, and in particular, to calculate the influence of intraocular pressure (IOP) on the eye resonance frequencies. Our mechanical model of the eye relies upon the theory of the mechanics of continuous media. The numerical model results from a modal analysis of the vibrations of the eye using a finite element method (FEM) for discretization. The eye can be schematically represented as a prestressed she

Christian Depeursinge

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MEMS for enhanced optical diagnosis in microscopy

Influence of shot noise on phase measurement accuracy in digital holographic microscopy

Process engineering and failure analysis of MEMS and MOEMS by Digital Holography Microscopy (DHM)

Polarization imaging by use of digital holography

Microlenses metrology with digital holographic microscopy

Digital holographic microscopy real-time monitoring of cytoarchitectural alterations during simulated microgravity

Enhanced robustness digital holographic microscopy for demanding environment of space biology

Digital holographic microscopy for the cytomorphological imaging of cells under zero gravity

Shot noise perturbations in digital holographic microscopy phase images

Digital Holographic Microscopy (DHM): Fast and robust 3D measurements with interferometric resolution for industrial inspection

Quantitative phase imaging in biomedicine

Realistic 3D coherent transfer function inverse filtering of complex fields

Holographic second harmonic generation (SHG) microscopy

Digital holography applied to microscopy

Spatial filtering and aperture apodization in digital holographic microscopy

Spatial analysis of erythrocyte membrane fluctuations by digital holographic microscopy

Complex index refraction tomography with sub ?/6-resolution

Shot noise influence in reconstructed phase image SNR in digital holographic microscopy

Measurement of absolute cell volume, osmotic membrane water permeability, and refractive index of transmembrane water and solute flux by digital holographic microscopy

A fluid-structure interaction problem in biomechanics: prestressed vibrations of the eye by the finite element method