A5026135138- Laser-induced spectroscopy and plasma
- Laser Design and Applications
- Laser Material Processing Techniques
- Atomic and Molecular Physics
- Ion-surface interactions and analysis
- Diamond and Carbon-based Materials Research
- Mass Spectrometry Techniques and Applications
- Spectroscopy and Laser Applications
- Solid-state spectroscopy and crystallography
- Advanced Chemical Physics Studies
- Atomic and Subatomic Physics Research
- Laser-Matter Interactions and Applications
- Thermography and Photoacoustic Techniques
- Plasma Diagnostics and Applications
- Laser-Plasma Interactions and Diagnostics
- Silicon Nanostructures and Photoluminescence
- Laser-Ablation Synthesis of Nanoparticles
- Micro and Nano Robotics
- Cold Atom Physics and Bose-Einstein Condensates
- Solid State Laser Technologies
- Quantum, superfluid, helium dynamics
- Soft Robotics and Applications
- Plasma Applications and Diagnostics
- Metal and Thin Film Mechanics
- Photorefractive and Nonlinear Optics
ETH Zurich
1965-2024
Kantonsspital Aarau
2024
Institute for Biomedical Engineering
2021
Instituto de Óptica "Daza de Valdés"
1998-2000
University of Hull
1996-1997
Infection et inflammation
1995-1996
Aix-Marseille Université
1994-1996
Centre National de la Recherche Scientifique
1995-1996
IBM Research - Thomas J. Watson Research Center
1981-1992
Endicott College
1991
Treating vascular diseases in the brain requires access to affected region inside body. This is usually accomplished through a minimally invasive technique that involves use of long, thin devices, such as wires and tubes, are manually maneuvered by clinician within bloodstream. By pushing, pulling, twisting, these devices navigated tortuous pathways blood vessels. The outcome procedure heavily relies on clinician’s skill device’s ability navigate target bloodstream, which often inhibited...
Pulsed laser radiation at 193, 248, or 308 nm can etch films of polyimide (DuPont KaptonTM). The mechanism this process has been examined by the chemical analysis condensible products, laser-induced fluorescence diatomic and measurement depth per pulse over a range fluences pulse. most important product as well only one room temperature is carbon. Laser-induced showed that C2 CN were present in ablation plume. At 248 nm, even below fluence threshold 0.08 J/cm2 for significant ablation, these...
A detailed study is made of the "conductivity plot" ($log\ensuremath{\sigma}T$ vs ${T}^{\ensuremath{-}1}$) for dc ionic conductivity, $\ensuremath{\sigma}$, NaCl crystals doped with various divalent cation impurities. This plot, when examined over a range from melting point down to -35\ifmmode^\circ\else\textdegree\fi{}C, divides itself into number distinct regions. Below intrinsic region in which cation-vacancy concentration equal impurity concentration. this plot steepens due occurrence...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotochemical cleavage of a polymeric solid: details the ultraviolet laser ablation poly(methyl methacrylate) at 193 nm and 248 nmR. Srinivasan, B. Braren, D. E. Seeger, R. W. DreyfusCite this: Macromolecules 1986, 19, 3, 916–921Publication Date (Print):March 1, 1986Publication History Published online1 May 2002Published inissue 1 March 1986https://pubs.acs.org/doi/10.1021/ma00157a074https://doi.org/10.1021/ma00157a074research-articleACS...
The formation of C2 in the ablation polymethyl methacrylate (PMMA) by 193- and 248-nm laser pulses was studied laser-induced fluorescence. is observable at a fluence 248 nm that well below threshold where significant etching takes place. opposite true 193 nm. velocity distribution diatomic form also measured found to approach but not exactly fit Maxwell–Boltzmann equation. Average translational energies as high 6 eV were recorded even for this product. other products PMMA or are methyl (MMA)...
We have used laser-induced fluorescence to measure the energy distributions of Al atoms and AlO molecules produced by excimer laser ablation Al2O3. Excimer fluences close threshold for were minimize effects gas phase collisions. The kinetic energies both species high, ∼4 eV ∼1 AlO, but rotational vibrational quite low, corresponding a temperature ∼600 K. These results rule out thermal vaporization provide indirect support an electronic mechanism.
Sodium-ion vacancies are introduced into sodium chloride crystals by the addition of following divalent cation impurities: ${\mathrm{Mg}}^{++}$, ${\mathrm{Mn}}^{++}$, ${\mathrm{Ca}}^{++}$, ${\mathrm{Zn}}^{++}$, ${\mathrm{Cd}}^{++}$, and ${\mathrm{Sr}}^{++}$. Below 150\ifmmode^\circ\else\textdegree\fi{}C, virtual negative charge a vacancy binds majority to impurity ions form complexes. The reorientation these dipolar complexes is observed in present experiments as transient dielectric...
Recent experiments on the dc ionic conductivity of NaCl crystals doped with divalent cation impurities led to a re-evaluation some basic constants for defect formation and motion in these crystals. The key parameter is energy εm vacancy. This has been determined from temperature dependence under conditions where concentration vacancies remains fixed. Such apply (1) range just below intrinsic region, (2) samples rapidly cooled 0°C such as prevent attainment an equilibrium degree association....
Abstract Magnetic navigation systems are used to precisely manipulate magnetically responsive materials enabling the realization of new minimally invasive procedures using magnetic medical devices. Their widespread applicability has been constrained by high infrastructure demands and costs. The study reports on a portable electromagnetic system, Navion, which is capable generating large field over workspace. system easy install in hospital operating rooms transportable through health care...
Bulk copper is laser etched with 193- and 351-nm excimer radiation. The transition from the thermal to plasma etch region studied by measuring densities kinetic energies of three species (Cu0, Cu+, Cu2 ) in plume. A unique laser-induced fluorescence experiment allows these be followed essentially simultaneously as a function fluence. Three separate types etching behavior are clearly evident (even within small fluence range ∼1–12.5 J/cm2 ); i.e., vaporization Cu, multiphoton ionization Cu...
Appreciable pairing of divalent metallic impurities with ${\mathrm{Na}}^{+}$ vacancies occurs in NaCl below 300\ifmmode^\circ\else\textdegree\fi{}C. The reorientation such pairs or complexes had previously been observed under an applied electric field. In the present work stress-induced doped Ca${\mathrm{Cl}}_{2}$ and Mn${\mathrm{Cl}}_{2}$ has studied by means internal friction measurements. An peak attributed to pair stress was near 100\ifmmode^\circ\else\textdegree\fi{}C for a vibration...
Ground-state populations of cationic and neutral Y, Ba, Cu, YO, BaO, CuO are monitored by laser-induced fluorescence during laser ablation ${\mathrm{YBa}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{7\mathrm{\ensuremath{-}}\mathrm{\ensuremath{\delta}}}$. 193-nm photons completely dissociate allowing the observation a subsequent reaction Cu atom with ${\mathrm{O}}_{2}$ to form CuO. As function pressure, signal increases maximum at approximately 120 mTorr ${\mathrm{O}}_{2}$, presumably minimizing...
A Michelson interferometer has been used as a direct quantitative probe for gas phase plasma formation in the UV excimer laser ablation of solids. Excimer fluence thresholds are determined and correlated with optical emission from electronically excited fragments.
Abstract
Received 17 November 1965DOI:https://doi.org/10.1103/PhysRevLett.16.165©1966 American Physical Society
We have used a single wire probe to measure time of flight velocities for copper photoablated with 248 nm pulsed excimer laser. For the range fluences, 1.6–12 J/cm2, we find ion in 1–2×106 cm/s. Langmuir theory determine densities and electron temperatures as function fluence target-probe separation. Results are consistent recent kinetic plasma theories.
Strong ionization signals have been observed in Ca following two-photon absorption to the bound, even-parity $J=0$ and $J=2$ states. Using known lines for calibration, 72 new states classified, their energies determined \ifmmode\pm\else\textpm\fi{} 0.1 ${\mathrm{cm}}^{\ensuremath{-}1}$. The a constant quantum defect, whereas do not.
Stimulated emission has been observed in the $Q1$ and some $P3$ lines of ${v}^{\ensuremath{'}}\ensuremath{\rightarrow}{v}^{\ensuremath{'}\ensuremath{'}}=1\ensuremath{-}4,2\ensuremath{-}5,2\ensuremath{-}6, \mathrm{and} 3\ensuremath{-}7$ Werner bands (${C}^{1}{\ensuremath{\Pi}}_{\mathrm{u}}\ensuremath{\rightarrow}{X}^{1}{{\ensuremath{\Sigma}}_{\mathrm{g}}}^{+}$) molecular hydrogen near 1200 \AA{}. Light pulses approximately 1 nsec duration were produced by bombarding gas with \ensuremath{\sim}...
Previous modelling of the matrix-assisted laser desorption/ionization (MALDI) process has had to rely on matrix solution optical absorptivities whereas value for solid phase is more appropriate. Absorption bands are usually broader solids than solutions due higher concentration in former, hence values generally overestimate absorptivity. In order rectify this shortcoming, present work reports absorption coefficient (α) sublimed MALDI films with measured thicknesses 50 600 nm. The compounds...
Energy levels of O${\mathrm{H}}^{\ensuremath{-}}$ in KCl crystals are evaluated from transitions due to resonant absorption electromagnetic energy. These interpreted a consistent way through model which the moves 3-dimensional set harmonic potentials. With respect lowest energy levels, i.e., those tunneling, microwave measurements show that splitting factor equals 5.5\ifmmode\pm\else\textpm\fi{}1.1 kMc/sec and apparent dipole moment this system $3.3\ifmmode\pm\else\textpm\fi{}0.6...