Studies Using High Intensity Pulsed Laser Beams

Abstract High-intensity focused ultrasound (HIFU) is used clinically to heat cells therapeutically or to destroy them through heat or cavitation. In homogeneous media, the highest wave amplitudes occur at a predictable focal region. However, HIFU is generally not used in the proximity of bones due to wave absorption and scattering. Ultrasound is passed through the skull in some clinical trials, but the complex geometry of the spine poses a greater targeting challenge and currently prohibits therapeutic ultrasound treatments near the vertebral column. This paper presents a comprehensive experimental study involving shadowgraphy and hydrophone measurements to determine the spatial distribution of pressure amplitudes from induced HIFU waves near vertebrae. First, a bone-like composite plate that is partially obstructing the induced waves is shown to break the conical HIFU form into two regions. Wave images are captured using pulsed laser shadowgraphy, and hydrophone measurements over the same region are compared to the shadowgraphy intensity plots to validate the procedure. Next, shadowgraphy is performed for an individual, clean, ex-vivo feline vertebra. The results indicate that shadowgraphy can be used to determine energy deposition patterns and to determine heating at a specific location. The latter is confirmed through additional temperature measurements. Overall, these laboratory experiments may help determine the efficacy of warming specific nerve cells within mammal vertebrae without causing damage to adjacent tissue.

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Acceleration characteristics of flyers driven by pulsed laser beams

High Power Laser and Particle Beams ◽

10.3788/hplpb20122411.2531 ◽

2012 ◽

Vol 24 (11) ◽

pp. 2531-2536 ◽

Cited By ~ 1

Author(s):

王飞 Wang Fei ◽

陈朗 Chen Lang ◽

伍俊英 Wu Junying ◽

孙崔源 Sun Cuiyuan

Keyword(s):

Pulsed Laser ◽

Laser Beams

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Self-pinching of pulsed laser beams during filamentary propagation

Optics Express ◽

10.1364/oe.17.016429 ◽

2009 ◽

Vol 17 (19) ◽

pp. 16429 ◽

Cited By ~ 17

Author(s):

Carsten Brée ◽

Ayhan Demircan ◽

Stefan Skupin ◽

Luc Bergé ◽

Günter Steinmeyer

Keyword(s):

Pulsed Laser ◽

Laser Beams

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Preparation of Silicon Carbide Nano-Particles Using a Pulsed Laser Deposition Method

MRS Proceedings ◽

10.1557/proc-818-m11.1.1 ◽

2004 ◽

Vol 818 ◽

Cited By ~ 1

Author(s):

H. Kawasaki ◽

Y. Suda ◽

T. Ohshima ◽

T. Ueda ◽

S. Nakashima

Keyword(s):

Thin Films ◽

Silicon Carbide ◽

Pulsed Laser Deposition ◽

Nd:Yag Laser ◽

Photoelectron Spectroscopy ◽

Pulsed Laser ◽

Nano Particles ◽

Laser Deposition ◽

Laser Beams ◽

Silicon Carbon

AbstractWe have developed a new pulsed laser deposition technique using two Nd:YAG laser beams for the nucleation of silicon carbide (SiC) crystalline nano-particles and single crystalline SiC thin films. Transmission electron microscopy and atomic force microscopy observation suggest that several nanometer size SiC particles can be prepared by the new pulsed laser deposition (PLD) method using two Nd:YAG laser beams (1064nm and 532nm). X ray photoelectron spectroscopy measurements suggest that the silicon/carbon composition ratio of the prepared SiC thin films can be controlled by laser fluence and wavelength.

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Microraman Study of Laser Ablated Gaas

MRS Proceedings ◽

10.1557/proc-354-687 ◽

1994 ◽

Vol 354 ◽

Author(s):

C. García ◽

J. Jiménez ◽

A.C. Prieto ◽

J. Ramos ◽

L.F. Sanz

Keyword(s):

Chemical Composition ◽

Structural Changes ◽

Pulsed Laser ◽

Optical Interferometry ◽

Laser Beams ◽

Surface Inspection ◽

Dopant Distribution ◽

Microraman Spectroscopy

AbstractMorphologic and structural changes induced by UV pulsed laser beams on GaAs are studied by means of surface inspection (optical interferometry) and MicroRaman spectroscopy. Crystal order and chemical composition (dopant distribution ) are shown to be changed by the ablation.

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Optimum laser parameters for 1D radiation pressure acceleration

Laser and Particle Beams ◽

10.1017/s0263034615000336 ◽

2015 ◽

Vol 33 (3) ◽

pp. 387-396 ◽

Cited By ~ 5

Author(s):

Peter Schmidt ◽

Oliver Boine-Frankenheim ◽

Peter Mulser

Keyword(s):

Laser Pulse ◽

Radiation Pressure ◽

Pulsed Laser ◽

Laser Beams ◽

Body Density ◽

One Dimensional ◽

Acceleration Mechanism ◽

The Past ◽

Commercial Code ◽

Foil Target

AbstractLaser ion acceleration (Wilks et al., 2001; Passoni et al., 2010) has become an interesting field of research in the past years. Several experiments, such as LIGHT (Schollmeier et al., 2008; Bagnoud et al., 2010; Busold et al., 2013; 2014a; 2014b) are performed worldwide. High intense, pulsed laser beams are used to generate and accelerate a plasma. For higher laser intensities (>1021 W cm−1), simulations (Esirkepov et al., 2004; Macchi et al., 2005; 2009; 2010; Robinson et al., 2008; Rykovanov et al., 2008; Henig et al., 2009; Schlegel et al., 2009; Shoucri et al., 2011; 2013; 2014; Kar et al., 2012; Korzhimanov et al., 2012; Shoucri, 2012) have revealed a new acceleration mechanism: The Radiation Pressure Acceleration. The entire foil target is accelerated by the radiation pressure of the laser pulse. Ideally, a sharp peak spectrum is generated, with energies up to GeV and nearly solid body density. This work faces on a detailed analysis of the acceleration mechanism in order to develop the optimum laser- and target parameters for the process. The analysis is supported by one-dimensional PIC simulations, using the commercial code VSim© Tech-X (2015).

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