Joachim Holzfuss

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Micromanipulation of sonoluminescing bubbles is achieved by generating a complex sound field consisting of spatially distributed modes of higher harmonics of a basic driving frequency. Bubbles can be manipulated in space and shifted to any desired spot. The interaction with the complex sound field also allows for specification of the violence of a bubble(More)
The authors have investigated the application of mode-locked and Q-switched Neodymium:YAG (Nd:YAG) lasers in ocular surgery by means of high-speed photography and hydrophone measurements. The incisive effect relies on the optical breakdown at the laser focus. Cavitation bubbles and acoustic transients are thereby generated. Their size and pressure amplitude(More)
In a certain parameter region, a single sonoluminescencing bubble is unstable against diffusion of gases and their chemical dissociation. Experiments show that a surface unstable bubble emits a microbubble and recoils. After this it exhibits specific dynamical features whereby the ambient radius changes in a nonmonotonic way. A numerical analysis identifies(More)
Numerical results are presented for hydrodynamic instabilities surrounding the parameter space of sonoluminescing bubbles. The Rayleigh-Taylor instability is shown to limit bubble oscillations only in a small region near a border at small radii in noisy environments. Also, two different noise-induced instabilities by secondary collapses are identified. The(More)
Existing methods of time series analysis of nonlinear dynamical systems deal with the dynamics on single (strange) attractors. We extend this method for systems that can be externally manipulated. We interact with a previously unknown system by perturbing it randomly and recording the responses. By following transients for a short time and approximating the(More)
In the parameter region for sonoluminescence of a single levitated bubble in a water-filled resonator it is observed that the bubble may have an enormous spatial stability leaving it "pinned" in the fluid and allowing it to emit light pulses of picosecond accuracy. We report here observations of a complex harmonic structure in the acoustic field surrounding(More)
Bubbles are levitated in a resonator driven by an ultrasound wave. Their highly nonlinear oscillations feature a strong collapse, where fluidlike densities and temperatures of several thousand degrees Kelvin are reached, resulting in the emission of ultrashort light pulses. Previous experiments and theories explained the observed stable bubble dynamic and(More)
In a model experiment using polyethylene membrane in balanced salt solution the processes which take place during posterior capsulotomy with pulsed Nd:YAG lasers were investigated by means of high-speed photography and hydrophone measurements. It was found that cavitation bubbles with a maximum diameter of 1.5 to 2.3 mm develop at the focal point even with(More)
We present a method for detecting and quantifying relationships between two ore more time series. It is based on the estimation of conditional entropies. In the case of continuous systems an appropriate conditional probability is calculated. Our method can be used for deciding, if one observable Y depends on another one X. If Y can be expressed as a(More)
Chemical oscillations are shown to be responsible for very low frequency modulations of a bubble oscillating nonlinearly in a high intensity ultrasound field. In the parameter space of incomplete dissociation near the onset of sonoluminescence a small bubble is shown to grow on a long time scale by the intake of dissolved air. Bubble collapses get hotter(More)
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