Christian Depeursinge

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Reflection digital holographic microscopy (DHM) is a very powerful technique allowing measuring topography with a sub-nanometer axial resolution from a single hologram acquisition. But as most of interferometer methods, the vertical range is limited to half the wavelength if numerical unwrapping procedure could not be applied (very high aspect ratio specimen). Nevertheless, it was already demonstrated that the use of dual-wavelength DHM allows increasing the vertical range up to several microns by saving th

This paper presents Digital Holographic Microscopy (DHM) quantitative measurements of transparent high aspect-ratio microstructures. Our experiment was performed using a digital holographic microscope in transmission configuration with a 60x magnification 1.3 NA oil immersion microscope objective, with a diode laser source at 664 nm. We used a calculation model based on the use of two immersion liquids for the experiment, the first one to resolve the phase jumps by using a refractive index liquid close to t

We report the experimental observation of systematically occurring phase singularities in coherent imaging of sub-Rayleigh distanced objects. A theory that relates the observation to the sub-Rayleigh distance is presented and compared with experimental mea ...

Quantitative Phase Imaging techniques including DHM have been applied recently in the field of cell imaging to monitor and quantify non-invasively dynamic cellular processes modifying cell morphology and/or content. Concretely, the DHM phase signal is highly sensitive to cell thickness and intracellular integral RI variations associated with transmembrane water movements. As net water flow across the cell membrane leads at the same time to changes in cell thickness and intracellular RI, the interpretation o

A method for the numerical reconstruction of digital holograms which allows simultaneously amplitude and quantitative phase contrast imaging. The reconstruction method computes the propagation of the field that would be diffracted by the hologram during a standard hologram reconstruction. The method requires the adjustment of several reconstruction parameters for the definition of a digital replica of the reference wave. The method includes a digital method for the correction of the phase aberrations. The m

Off-axis holograms recorded with a CCD camera are numerically reconstructed with a calculation of scalar diffraction in the Fresnel approximation. We show that the zero order of diffraction and the twin image can be digitally eliminated by means of filtering their associated spatial frequencies in the computed Fourier transform of the hologram. We show that this operation enhances the contrast of the reconstructed images and reduces the noise produced by parasitic reflections reaching the hologram plane wit

Femtosecond laser pulses used in a regime below the ablation threshold have two noticeable effects on Fused Silica (a-SiO2): they locally increase the material refractive index and modify its HF etching selectivity. The nature of the structural changes ind ...

A method is proposed for designing apodized apertures with a transmission profile which follows a curve defined using a cubic spline interpolation. The method is applied in digital holographic microscopy to perform digitally the apodization of the aperture of holograms recorded by a CCD camera. The transmission of the apodized aperture is entirely defined by four parameters which are adjusted iteratively to minimize intensity and phase fluctuations appearing in the images obtained by numerical reconstructio

We report on a method called Digital Holographic Microscopy (DHM) for the numerical reconstruction of digital holograms taken with a microscope. It allows for 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 an accuracy in the nanometer range along the optical axis. A single hologram is needed for reconstruct

Femtosecond laser irradiation has various noticeable effects on fused silica. It can locally increase the index of refraction and modify the material chemical selectivity. Regions that have been exposed to the laser are etched hundred fold faster than unexposed regions. These effects are of practical importance from an application point-of-view and open new opportunities for the development of integrated photonics devices that combine structural and optical functions. Various observations reported in the li

The authors have developed a live-cell multimodality microscope combining epifluorescence with digital holographic microscopy; it has been implemented with a decoupling procedure allowing to separately measure from the quantitative phase important cell par ...

We present first results on a method enabling mechanical scanning-free tomography with submicrometer axial resolution by multiple-wavelength digital holographic microscopy. By sequentially acquiring reflection holograms and summing 20 wavefronts equally sp ...

Red blood cells (RBCs) present unique reversible shape deformability, essential for both function and survival, resulting notably in cell membrane fluctuations (CMF). These CMF have been subject of many studies in order to obtain a better understanding of ...

Quantitative phase images make digital holographic microscopy (DHM) an excellent instrument for metrological, but also for biological applications, where it can reveal deformations and morphological details at ultrahigh resolution in the order of a few nanometers only, while also precisely determining the refractive index across a sample (e.g. cell or neuron). On the other hand, non-linear light-matter interactions have also proved very useful in microscopy. For instance, second harmonic generation (SHG) al

We propose and experimentally demonstrate a digital holographic camera which can be attached to the camera port of a conventional microscope for obtaining digital holograms in a self-reference configuration, under short coherence illumination and in a sing ...

The limited depth-of-field is a main drawback of microscopy that prevents from observing, for example, thick semi-transparent objects with all their features in focus. Several algorithms have been developed during the past years to fuse images having various planes of focus and thus obtain a completely focused image with virtually extended depth-of-field. We present a comparison of several of these methods in the particular field of digital holographic microscopy, taking advantage of some of the main proper

The point spread function is widely used to characterize the three-dimensional imaging capabilities of an optical system. Usually, attention is paid only to the intensity point spread function, whereas the phase point spread function is most often neglecte ...

In the past decade, quantitative phase imaging gave a new dimension to optical microscopy, and the recent extension of digital holography techniques to nonlinear microscopy appears very promising, for the phase of nonlinear signal provides additional infor ...

Digital holography microscopy (DHM) is an optical technique which provides phase images yielding quantitative information about cell structure and cellular dynamics. Furthermore, the quantitative phase images allow the derivation of other parameters, inclu ...

We introduce a microscopic method that determines quantitative optical properties beyond the optical diffraction limit and allows direct imaging of unstained living biological specimens. In established holographic microscopy, complex fields are measured us ...

Christian Depeursinge

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Several micron-range measurements with sub-nanometric resolution by the use of dual-wavelength digital holography and vertical scanning

Measurements of corner cubes microstructures by high-magnification digital holographic microscopy

Sub-Rayleigh resolution by phase imaging

Quantitative Measurement of absolute cell volume and intracellular integral refractive index (RI) with Dual-wavelength Digital Holographic Microscopy (DHM)

Method for simultaneous amplitude and quantitative phase contrast imaging by adjusting reconstruction parameters for definition of digital replica of reference wave and aberration parameters correction digitally

Spatial filtering for zero-order and twin-image elimination in digital off-axis holography

Nanoindentation and birefringence measurements on fused silica specimen exposed to low-energy femtosecond pulses

Aperture apodization using cubic spline interpolation: application in digital holographic microscopy

Digital Holographic Microscopy applied to Metrology

Investigation of Femtosecond Laser Irradiation on Fused Silica

Cell Morphology and Intracellular Ionic Homeostasis explored with a Multimodal Approach combining Epifluorescence and Digital Holographic Microscopy

Submicrometer tomography of cells by multiple-wavelength digital holographic microscopy in reflection

Spatially-Resolved Eigenmode Decomposition of Red Blood Cells Membrane Fluctuations Questions the Role of ATP in Flickering

Digital holography for second harmonic microscopy

Off-axis digital holographic camera for quantitative phase microscopy

Depth-of-field extension and 3D reconstruction in digital holographic microscopy

On the complex three-dimensional amplitude point spread function of lenses and microscope objectives: theoretical aspects, simulations and measurements by digital holography

Real time, nanometric 3D-tracking of nanoparticles made possible by second harmonic generation digital holographic microscopy

Noninvasive characterization of the fission yeast cell cycle by monitoring dry mass with digital holographic microscopy

Marker-free phase nanoscopy