Christian Depeursinge

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We present fast high-roughness and non-contact surface measurements by digital holographic microscopy (DHM). By using single- and dual-wavelength operation modes, coupled with advanced image stitching and non-measured points management methods, the technique enables two-dimensional roughness measurements up to the micrometer (N6). The sample is mechanically scanned over a surface up to 5 × 0.3 mm2 with 17 holograms each acquired in less than 500 µs, the corresponding phase images stitched together by softwa

The invention relates to a method and apparatus for topological or shape measurement of objects of any size, by using an interferometric technique comprising an optical source, with selectable coherence, allowing contouring from single shot interferograms ...

Optical tomography provides three-dimensional data of the measured specimen, while quantitative phase imaging enables measuring the induced phase-shifts. Combining those two technologies makes possible to get three-dimensional refractive index reconstruction. This can be achieved by introducing a scan in the measurement process, which can be done in several ways. We present and compare results of tomographic measurements, taken either in angle-scanning or wavelength-scanning approach, respectively in transm

A demonstration of the ability of digital holography to image and to measure spatial variations of the polarisation of an object wave with a single image acquisition is presented. This is achieved by recording a hologram with two reference beams presenting orthogonal polarisations and different propagation directions. A CCD camera is used to record the hologram and the reconstruction is performed numerically.

Digital holography microscopy (DHM) is an optical microscopy technique which allows recording non-invasively the phase shift induced by living cells with nanometric sensitivity. Here, we exploit the phase signal as an indicator of dry mass (related to the protein concentration). This parameter allows monitoring the protein production rate and its evolution during the cell cycle.

We propose and experimentally demonstrate a system in which off-axis digital holographic microscopy is realized using a broadband illumination source. Single-shot holographic measurements are enabled, while the coherence noise is removed thanks to the broa ...

An `in situ' holographic technique, based on the use of a flexible miniaturized endoscope (diameter less than 1 mm) has been developed for medical applications. The holographic process provides quantitative information on the 3-D geometry of the observed scene, including deformations and movements. The holographic system presented here is based on the use of a multimode fiber bundle (MMB) as a recording medium for the endoscopic holograms. The hologram is obtained by the interference between the light refle

We present experimental investigation of a new reconstruction method for off-axis digital holographic microscopy (DHM). This method effectively suppresses the object auto-correlation, commonly called the zero-order term, from holographic measurements, thereby suppressing the artifacts generated by the intensities of the two beams employed for interference from complex wavefield reconstruction. The algorithm is based on non-linear filtering, and can be applied to standard DHM setups, with realistic recording

We report on a method to achieve real-time dual-wavelength digital holographic microscopy with a single hologram acquisition. By recording both interferograms from two laser sources at different wavelengths in only one spatially-multiplexed digital hologram, we are able to independently propagate and apply numerical corrections on both wavefronts in order to obtain a beat-wavelength phase map of the specimen. This beat-wavelength being up to 10-100 times larger than the original wavelengths, we are in a sit

Three approaches for visualization of transparent micro-objects from holographic data using phase-only SLMs are described. The objects are silicon micro-lenses captured in the near infrared by means of digital holographic microscopy and a simulated weakly ...

The concept of numerical parametric lenses (NPL) is introduced to achieve wavefront reconstruction in digital holography. It is shown that operations usually performed by optical components and described in ray geometrical optics, such as image shifting, m ...

Three-dimensional optical imaging by tomographic techniques is presented, especially with object rotation in a transmission configuration. In digital holographic microscopy, the complex field is measured, which permits either to study transparent objects with varying index of refraction or to compute diffraction tomography in which the phase is needed.

3D Refractive Index (RI) tomography appears as a challenging perspective in the observation of microscopic 3D objects, biological cells in particular. Recent developments in Digital Holographic Microscopy have permitted to achieve accurate RI 3D images.

Digital Holographic Microscopes (DHM) enables recording the whole information necessary to provide real time nanometric vertical displacement measurements with a single image acquisition. The use of fast acquisition camera or stroboscopic acquisition mode makes these new systems ideal tools for investigating the topography and dynamical behavior of MEMS and MOEMS. This is illustrated by the investigation of resonant frequencies of a dual axis micromirror. This enables the definition of the linear, non-linea

Low coherence, digital holographic microscopy (LCDHM) is a new 3D imaging technique combining the advantages of digital holographic microscopy with those of reduced coherence interferometry. This gives the possibility to perform tomography of 3D objects while maintaining the excellent performances of DHM. A tomographic depth resolution of 11 mum has been achieved as a proof of principle. Images of the epithelial cells of the porcine cornea are presented.

We show that digital holography can be combined easily with optical coherence tomography approach. Varying the reference path length is the means used to acquire a series of holograms at different depths, providing after reconstruction images of slices at ...

Based on truncated inverse filtering, a theory for deconvolution of complex fields is studied. The validity of the theory is verified by comparing with experimental data from digital holographic microscopy (DHM) using a high-NA system (NA=0.95). Comparison ...

We introduce Endoscopic Low Coherence Interferometry to obtain topology of upper airways through commonly used rigid endoscopes. Quantitative dimensioning of upper airways pathologies is crucial to provide maximum health recovery chances, for example in order to choose the correct stent to treat endoluminal obstructing pathologies. Our device is fully compatible with procedures used in day-to-day examinations and can potentially be brought to bedside. Besides this, the approach described here can be almost

We address the problem of exact complex-wave reconstruction in digital holography. We show that, by confining the object-wave modulation to one quadrant of the frequency domain, and by maintaining a reference-wave intensity higher than that of the object, ...

The invention concerns a method of and an apparatus for the measurement of the Amplitude Point Spread Function (APSF), of an Optical Imaging System (OIS), wherein the APSF is defined as the complex field distribution of the beam delivered by the OIS and or ...

Christian Depeursinge

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Fast non-contact surface roughness measurements up to the micrometer range by dual-wavelength digital holographic microscopy

Method and apparatus for 3d object shape and surface topology measurements by contour depth extraction acquired in a single shot

Optical tomography by digital holographic microscopy

Single acquisition polarisation imaging with digital holography

Non-invasive dry mass determination and monitoring at the single cell level with digital holographic microscopy

Towards an incoherent off-axis digital holographic microscope

Microendoscopic holography with flexible fiber bundle: experimental approach

Artifact-free reconstruction from off-axis digital holograms through nonlinear filtering

Real-time dual-wavelength digital holographic microscopy with a single hologram

Optical reconstruction of transparent objects with phase-only SLMs

Numerical parametric lens for shifting, magnification and complete aberration compensation in digital holographic microscopy

Optical tomography with digital holographic microscopy

Refractive Index Tomography by Digital Holographic Microscopy

Digital Holographic Microscopy (DHM) for metrology and dynamic characterization of MEMS and MOEMS

Low coherence digital holographic tomography

Time-domain optical coherence tomography with digital holographic microscopy

Microscopy image resolution improvement by deconvolution of complex fields

Endoscopic low coherence interferometry in upper airways

Exact Complex-Wave Reconstruction in Digital Holography

Method and apparatus to measure and compute the amplitude point spread function and associated parameters of a coherent optical imaging system