A5108167127- Advanced Fluorescence Microscopy Techniques
- Laser-Matter Interactions and Applications
- Photoacoustic and Ultrasonic Imaging
- Advanced Fiber Laser Technologies
- Optical Coherence Tomography Applications
- Spectroscopy Techniques in Biomedical and Chemical Research
- Nonlinear Optical Materials Studies
- Laser Material Processing Techniques
- Optical Imaging and Spectroscopy Techniques
- Single-cell and spatial transcriptomics
- Ocular and Laser Science Research
- 3D Printing in Biomedical Research
- Photoreceptor and optogenetics research
- Spectroscopy and Quantum Chemical Studies
- Nonlinear Optical Materials Research
- Data Stream Mining Techniques
- Laser Design and Applications
- Mass Spectrometry Techniques and Applications
- Advanced Optical Sensing Technologies
- Cell Image Analysis Techniques
- Analytical Chemistry and Sensors
- Digital Holography and Microscopy
- Laser-Plasma Interactions and Diagnostics
- Optical Polarization and Ellipsometry
- Advanced X-ray and CT Imaging
HES-SO Arc
2022-2023
HES-SO University of Applied Sciences and Arts Western Switzerland
2016-2023
HES-SO Genève
2023
École Polytechnique Fédérale de Lausanne
2014-2019
Laboratoire d'Optique Appliquée
2017
Charles Humbert 8
2017
University of Geneva
2006-2013
Institutul de Fizică Atomică
2007-2011
Institute of Atomic Energy
2007-2010
École Normale Supérieure - PSL
2007
Nonlinear optical nanocrystals have been recently introduced as a promising alternative to fluorescent probes for multiphoton microscopy. We present the first time complete survey of properties five nanomaterials (KNbO(3), LiNbO(3), BaTiO(3), KTP, and ZnO), describing their preparation stabilization providing quantitative estimations nonlinear response. In light prospective use biological clinical markers, we assess biocompatibility on human healthy cancerous cell lines. Finally, demonstrate...
We demonstrate the possibility to excite second-harmonic (SH) active Fe(IO(3))(3) nanocrystals with two distinct laser sources at 800 and 1550 nm, we show, by a complementary experimental numerical study, how wavelength flexibility inherent non-phase-matched SH nanoparticles can be efficiently exploited increase imaging penetration depth of markers embedded in biological samples.
We present a Raman distributed temperature sensor based on standard telecom single mode fibers and efficient polarization-independent superconducting nanowire photon detectors. Our device shows 3 cm 1.5 °C resolution 5 m fiber upon one minute integration. show that spatial is limited by the laser pulse width not detection system. Moreover, for long minimum distance measurable step change increases of around 4 per km length, because chromatic dispersion at Stokes Anti-Stokes wavelengths....
Hyper Rayleigh scattering (HRS) and second harmonic (SH) microscopy were used to study the order nonlinear optical response of ZnO BaTiO3 nanocrystals, which have been recently proposed as new markers for bioimaging. HRS, combined with dynamic light scattering, was first retrieve hyperpolarizabilities coefficients both type nanocrystals. The results indicate that main contribution SH signal is related bulk noncentrosymmetric structure particles. Successively, we carried out inspection...
We present a novel extended-focus optical coherence microscope (OCM) attaining 0.7 μm axial and 0.4 lateral resolution maintained over depth of 40 μm, while preserving the advantages Fourier domain OCM. Our system uses an ultra-broad spectrum from supercontinuum laser source. As spans near-infrared to visible wavelengths (240 nm in bandwidth), we call visOCM. The combination such broad with high-NA objective creates almost isotropic 3D submicron resolution. analyze imaging performance visOCM...
We present a technique to characterize ultrashort pulses at the focal plane of high numerical aperture objective with unprecedented spatial resolution, by performing FROG measurement single nanocrystal as nonlinear medium.This approach can be extended develop novel phase-sensitive techniques in laser scanning microscopy, probing microscopic environment monitoring phase and amplitude distortions femtosecond pulses.
Abstract Potassium niobate nonlinear nanoparticles are used for the first time to monitor evolution of embryonic stem cells (ESC) by second harmonic microscopy. These particles feature complete absence photo‐bleaching and unlimited excitation wavelength flexibility. The potential this approach is made evident tissue‐regeneration studies applications, capturing a high‐speed movie ESC‐derived cardiomyocytes autonomously beating within cluster. Time‐resolved data analyzed retrieve 3D...
In recent years, three-dimensional mesoscopic imaging has gained significant importance in life sciences for fundamental studies at the whole-organ level. this manuscript, we present an optical projection tomography (OPT) method designed of intact mouse brain. The system features isotropic resolution ~50 µm and acquisition time four to eight minutes, using a 3-day optimized clearing protocol. Imaging brain autofluorescence 3D reveals details neuroanatomy, while use fluorescent labels...
Ultrahigh power laser pulses delivered by the Alisé beamline (26J, 32TW pulses) have been sent vertically into atmosphere. The highly nonlinear propagation of beam in air gives rise to more than 400 self-guided filaments. This extremely powerful bundle filaments generates a supercontinuum propagating up stratosphere, beyond 20km. constitutes highest “atmospheric white-light laser” date.
We demonstrate the excitation of second harmonic radiation noncentrosymmetric nanoparticles dispersed on a planar optical waveguide by evanescent field guided mode. Polarization imaging reveals information orientation crystal axis individual nanoparticles. Interference patterns generated from adjacent particles at frequency are--to authors knowledge--observed for first time. The actual form interference pattern is explained basis dipole model, taking into account nanoparticles' orientation,...
We have applied a multiobjective genetic algorithm to the optimization of multiphoton-excited fluorescence. Our study shows advantages that this approach can offer experiments based on adaptive shaping femtosecond pulses. The outperforms single-objective optimizations, being totally independent from bias user defined parameters and giving simultaneous access large set feasible solutions. global inspection their ensemble represents powerful support unravel connections between pulse spectral...
We report a bioinspired multifunctional albumin derived polypeptide coating comprising grafted poly(ethylene oxide) chains, multiple copies of the HIV TAT peptide enabling cellular uptake as well mitochondria targeting triphenyl-phosphonium (TPP) groups. Exploring these copolymers for passivating gold nanoparticles (Au NPs) yielded (i) NIR-emitting markers in confocal microscopy and (ii) photo-thermal active probes optical coherence microscopy. demonstrate great potential such...
We describe the performance of a reflective pulse-shaper based on Micro-ElectroMechanical System (MEMS) linear mirror array.It represents substantial upgrade preceding release [Opt.Lett.35, 3102 (2010)] as it allows simultaneous piston and tilt motion, allowing both phase-and binary amplitude-shaping with no wavelength restriction.Moreover, we show how combination in-axis movement can be used for active correction spatial chirp.
Abstract We present a 3D time-lapse imaging method for monitoring mitochondrial dynamics in living HeLa cells based on photothermal optical coherence microscopy and using novel surface functionalization of gold nanoparticles. The biocompatible protein-based biopolymer coating contains multiple functional groups which impart better cellular uptake mitochondria targeting efficiency. high stability the nanoparticles allows continuous over an extended time up to 3000 seconds without significant...
We demonstrate the capabilities of a new optical microelectromechanical systems device that we specifically developed for broadband femtosecond pulse shaping. It consists one-dimensional array 100 independently addressable, high-aspect-ratio micromirrors with up to 3μm stroke. apply linear and quadratic phase modulations demonstrating temporal compression 800 400nm pulses. Because device's surface flatness, stroke, stroke resolution, shaping over an unprecedented bandwidth is attainable.
We present an in-detail description of the design, simulation, fabrication, and packaging a linear micromirror array specifically designed for temporal pulse shaping ultrashort laser pulses. The innovative features this device include novel comb-drive actuator allowing both piston tilt motion phase- amplitude-shaping, X-shaped laterally reinforced spring preventing lateral snap-in while providing high flexibility degrees freedom.
We show how an ultrafast pump–pump excitation induces strong fluorescence depletion in biological samples, such as bacteria-containing droplets, contrast with fluorescent interferents, polycyclic aromatic compounds, despite similar spectroscopic properties. Application to the optical remote discrimination of biotic versus non-biotic particles is proposed. Further improvement required allow one pathogenic among other non-pathogenic micro-organisms. This improved selectivity may be reached...
In diabetes, pancreatic β-cells play a key role.These cells are clustered within structures called islets of Langerhans inside the pancreas and produce insulin, which is directly secreted into blood stream.The dense vascularization critical for maintaining proper regulation glucose homeostasis known to be affected from early stage diabetes.The deep localization these in abdominal cavity renders their vivo visualization challenging task.A fast label-free imaging method with high spatial...
The activity of the GAP-Biophotonics research group at University Geneva in field coherent control for discriminating similar biomolecules, such as flavins, proteins and DNA bases, is presented future developments are discussed.
Extended-focus optical coherence tomography (xf-OCT) is a variant of (OCT) wherein the illumination and/or detection modes are engineered to provide constant diffractionless lateral resolution over an extended depth field (typically 3 10× Rayleigh range). xf-OCT systems operating at 800 nm have been devised and used in past image brain structures high-resolution vivo, but limited ∼500 μm penetration due their short wavelength. Here we present system optimized deeper within cortex by using...
Optical coherence microscopy (OCM) is an interferometric technique providing 3D images of biological samples with micrometric resolution and penetration depth several hundreds micrometers. OCM differs from optical tomography (OCT) in that it uses a high numerical aperture (NA) objective to achieve lateral resolution. However, the NA also reduces depth-of-field (DOF), scaling 1/NA2. Interferometric synthetic (ISAM) computed imaging solution this trade-off between DOF. An alternative hardware...