A5033992908- Laser Material Processing Techniques
- Ocular and Laser Science Research
- Laser-induced spectroscopy and plasma
- Advanced Fluorescence Microscopy Techniques
- Optical Coherence Tomography Applications
- Nonlinear Optical Materials Studies
- Advanced Surface Polishing Techniques
- Photoacoustic and Ultrasonic Imaging
- Diamond and Carbon-based Materials Research
- Intraocular Surgery and Lenses
- Photodynamic Therapy Research Studies
- Corneal surgery and disorders
- Ion-surface interactions and analysis
- Laser Design and Applications
- Cultural Heritage Materials Analysis
- Laser-Ablation Synthesis of Nanoparticles
- Skin Protection and Aging
- 3D Printing in Biomedical Research
- Neuroscience and Neural Engineering
- Photoreceptor and optogenetics research
- Wound Healing and Treatments
- Retinal Development and Disorders
- High-pressure geophysics and materials
- Optical Imaging and Spectroscopy Techniques
- Metal and Thin Film Mechanics
Fraunhofer Institute for Biomedical Engineering
2010-2024
Fraunhofer Society
2009-2011
JenLab (Germany)
2005-2008
Laboratoire Hubert Curien
2002-2008
Université Jean Monnet
2000-2005
Centre National de la Recherche Scientifique
2001-2005
University of Stuttgart
2005
Laboratoire Traitement du Signal et de l'Image
2005
Mines Saint-Étienne
2002
This letter presents a method aimed at quantifying the dimensions of heat-affected zone (HAZ), produced during nanosecond and femtosecond laser–matter interactions. According to this method, 0.1 μm thick Al samples were microdrilled observed by transmission electronic microscopy technique. The holes laser fluences above ablation threshold in both regimes (i.e., 5 2 J/cm2, respectively). grain size was near microholes. main conclusion is that 40 wide HAZ induced pulses, whereas regime does...
Ablation of Cu and Al targets has been performed with 170 fs laser pulses in the intensity range ${10}^{12}\text{--}{10}^{14}\phantom{\rule{0.3em}{0ex}}\mathrm{W}\phantom{\rule{0.2em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}2}$. We compare measured removal depth 1D hydrodynamic simulations. The electron-ion temperature decoupling is taken into account using standard two-temperature model. influence early heat transfer by electronic thermal conduction on material expansion mechanical behavior...
Techniques based on laser scanning microscopes for nanoprocessing of periodic structures silicon with ultra-short pulses have been developed. Ripples 800-900 nm spacing were obtained after irradiation at a wavelength 1040 nm, repetition rate 10 kHz and fluence 2 J/cm2 in air. Smaller features 70-100nm achieved oil 800 90 MHz 200-300 mJ/cm2 by using high numerical focusing objective.
Large-area high-spatial-frequency patterns (HSFLs) of λ/6 periodicity have been generated by a nanojoule-femtosecond laser scanning technique (80 MHz, 170 fs, 700–950 nm) at the silicon–air interface. The excellent large-area uniformity allowed reproducible and accurate measurements periodicity. Variation experimental parameters as illumination geometry, pulse energy number showed no influence on ripple spacing. A wavelength dependence was observed compared to current models HSFL formation....
Periodic high spatial frequency ripples structures have been generated in silicon under femtosecond laser pulses irradiation. The period of the is wavelength dependent. It increases from 110 up to 160 nm when varies 700 950 nm, respectively. We propose a refined model second harmonic generation spacing theory Λ=λ/2nλ∗ taking into account modified excited refractive index n∗ related Drude model. Good agreement found between experimental results and presented revisited
We report on the generation of high spatial frequency LIPSS (HSFL) in silicon and germanium induced by nanojoule femtosecond laser pulses at repetition rate air. The periodicity ripples is found to be 125 nm for 98 germanium. formation these HSFL seems second harmonic (SHG) periods agree quite well with a λ/2n-law. Reproducible accurate patterning uniform surface areas up 100 mm2 can performed using versatile processing workstation.
Periodic high spatial frequency ripples structures (HSFL) have been generated in silicon (Si) and germanium (Ge) at very low fluence below or close to the melting threshold, different wavelengths repetition rate femtosecond laser pulses (80 MHz, 700–950 nm, 170 fs). HSFL initiation, formation, arrangement combine structural modification of surface initiated by heat accumulation successive with second harmonic generation. are wavelength dependent refractive index plays a central role on their...
We report on a nonlinear optical endoscope that adopts hollow core photonic crystal fiber for single-mode illumination delivery and multimode one signal collection. Femtosecond laser pulses up to 100 mW can be delivered at centered wavelength of 800 nm. The two-photon fluorescence response our system is shown have axial lateral resolutions 5.8 microm 0.6 respectively. Fluorescence detection was obtained different wavelengths between 790 840 nm which could allow SHG example. maximal...
Background/purpose: The aim of this study was to demonstrate the effects selected plant extracts in a cosmetic cream on dermal network components after 3-month treatment using an vivo multiphoton tomographic device. Methods: Twenty-four Caucasian women aged between 45 and 65 applied randomly emulsion B containing active ingredients (soy jasmine) twice day one arm its vehicle A (without ingredients) other during 3 months. Measurements were performed internal side forearm before starting (T0),...
We present a rigid miniaturized optical system block fiber-optic two-photon endoscope based on compact two-axis piezo scanner and miniature high (0.65) NA GRIN lens objective. The is scanned as whole by allowing always an on-axis beam irradiation of the system. A photonic crystal fiber used for excitation ultrashort laser pulses can be delivered with typical power up to 100 mW at 800 nm. Two-photon fluorescence signal collected use multimode fiber. Lateral resolution values were...
Silicon wafers were structured with a femtosecond laser on the cm2 scale high spatial frequency laser-induced periodic surface structures. These areas are characterized by regular parallel ripples period of order 100 nm. The particular ripple spacing is determined illumination wavelength tunable laser. cellular reaction to silicon and same materials, coated calcium phosphate nanoparticles electrophoretic deposition, was studied using L929 fibroblasts, human mesenchymal stem cells, epithelial...
Multiphoton tomography of human skin and nanosurgery chromosomes have been performed with a 1GHz repetition rate laser by the use commercially available femtosecond multiphoton tomograph DermaInspect as well compact galvoscanning microscope. We autofluorescence up to 100μm in depth skin. Submicron cutting lines hole drillings conducted on labeled chromosomes.
Purpose: To study parameters for ocular femtosecond laser surgery in terms of process efficiency and safety aspects using ultraviolet (UV) pulses. Methods: Studies on corneal flap processing enucleated porcine eyes were performed a newly developed ytterbium-doped gain media source. Ultraviolet pulses centered at wavelength 345 nm working repetition rate 100 kHz generated by the third harmonics 1035-nm fundamental wavelength. Results: Flaps with diameter 6 mm thickness µm created less than 2...
Abstract Purpose To develop and evaluate a photovoltaic, wireless wide‐field epiretinal prosthesis for the treatment of retinitis pigmentosa. Methods A mosaic array thinned silicon‐based photodiodes with integrated thin‐film stimulation electrodes was fabricated flexible polyimide substrate film to form film‐based miniaturized electronic system optical power signal transmission electrostimulation. Manufactured implants were characterized respect their optoelectronic performance...
We report on investigations of fine cross-sectional cuts performed by focused ion beam periodic high spatial frequency ripples generated large areas silicon in air under ultrashort low energy pulses irradiation at repetition rate. The morphology, depth profile, and aspect ratio which was found to be 1:1 are quite independent from the number applied even if a slight decrease energies pulses. Furthermore, orientation HSFL is perpendicular polarization profile cross sections not influenced...