Deep Etching in Silicon Using a Laser Beam Delivered by a Water Jet

2007 ◽  
Author(s):  
D. Wood
Keyword(s):  
Laser Beam ◽  
Water Jet ◽  
Deep Etching

scholarly journals The First Coupling of a Laser Beam to a Water Jet

2021 ◽  
Vol 18 (1) ◽  
pp. 72-76
Author(s):  
Nitin Shankar
Keyword(s):  
Laser Beam ◽  
Water Jet

Method of Removing Graffiti from Surface of Concrete

2006 ◽  
Vol 302-303 ◽  
pp. 363-370 ◽  
Author(s):  
Isamu Matsui ◽  
Atsushi Onda ◽  
Sachiyo Shinozaki ◽  
Eitou Kyo ◽  
Kaori Nagai ◽  
...  
Keyword(s):  
High Pressure ◽  
Laser Beam ◽  
Comparative Study ◽  
Sodium Bicarbonate ◽  
Laser Irradiation ◽  
Water Jet ◽  
Emulsion Paint ◽  
Pressure Water ◽  
High Pressure Water Jet ◽  
Graffiti Removal

The appearance of buildings and towns is ruined by graffiti drawn on walls made of concrete or brick. Much money and labor are spent in removing graffiti from such rough surface. This paper is a comparative study of the laser irradiation method and the high-pressure water jet method for removing graffiti from the surface of concrete. The former uses a YAG laser beam and the later uses water containing sodium bicarbonate particles. The graffiti were drawn in nine colors on the surface of concrete specimens using oil spray paint and emulsion spray paint. The main results of this study are as follows: Graffiti drawn with oil paint is easier to remove than that with emulsion paint. Yellow and orange colors are harder to remove compared to other colors. In both methods (laser irradiation and water jet) of removal, the surface of concrete is damaged only slightly. Overall, the laser irradiation method appears to be more effective for graffiti removal than the water jet method.

Stress Improvement by Laser Peening in the Air

2017 ◽  
Author(s):  
Souichi Ueno ◽  
Akihiro Tsuji ◽  
Hiroyuki Adachi ◽  
Tatsuya Naito
Keyword(s):  
Residual Stress ◽  
Laser Beam ◽  
Nozzle Exit ◽  
Laser Energy ◽  
Water Environment ◽  
Water Jet ◽  
Laser Peening ◽  
Potential Core ◽  
Spot Diameter ◽  
Pulse Density

Underwater laser peening (LP) system has been developed for the purpose of preventing occurrence of Stress Corrosion Cracking. Toshiba has already applied LP for actual nuclear reactors, such as Control-Rot Drive housings in BWR and bottom mounted instrumentations in PWR and so on. At the same time, LP system in the air is expected since Reactor Vessel Head (RVH) is set on an operating floor during outage. In this study, LP system in the air was proposed which employs laser beam irradiation with concentric water jet. LP uses shock waves made by underwater confinement of plasma generated during laser abrasion which enables to induce compressive residual stress at 1mm in depth by optimizing laser energy, laser spot diameter and pulse density. A water jet has the functions of transmitting a laser beam without attenuating power and creating partial under water environment in the air. Hence potential core, which has no disturbance area in a water jet, should be increased in diameter and longer in distance from nozzle exit. LP tests in the air were performed by using the developed nozzles and measurements of residual stress were conducted. Test conditions are below; 70 mJ in laser energy, 1.0 mm in spot diameter, more than 30 mm in distance from nozzle exit to irradiation point, 36 shot/mm2 in pulse density, 90 degree in irradiation angle between laser axis and surface direction of irradiated area. Material of specimens was Alloy 600 nickel based alloy. Residual stress was measured by X-ray diffraction. It was confirmed that stress state at 1.0 mm in depth from the surface indicates compressive stress. These results concluded that LP in the air was conducted successfully.

Precision Processing of Composites: Laser Beam and Water Jet Abrasion Techniques

2000 ◽  
Vol 2 (3) ◽  
pp. 100-104 ◽  
Author(s):  
U. Bauch ◽  
J. Bliedtner ◽  
H. Müller ◽  
M. Pitzschler ◽  
G. Staupendahl
Keyword(s):  
Laser Beam ◽  
Water Jet ◽  
Processing Of Composites

E125 Laser cutting technology which use the water jet guiding the laser beam : Application examination for the thick plate cutting

2013 ◽  
Vol 2013.18 (0) ◽  
pp. 171-172
Author(s):  
Katsunori SHIIHARA ◽  
Itaru CHIDA ◽  
Miyuki AKIBA ◽  
Rie SUMIYA ◽  
Kota Nomura
Keyword(s):  
Laser Beam ◽  
Laser Cutting ◽  
Thick Plate ◽  
Water Jet

Nd: YAG Laser with Water Jet Stream — A New Transmission System with a Water-Guided Laser Beam

1988 ◽  
pp. 241-244
Author(s):  
R. Sander ◽  
H. Poesl ◽  
F. Frank ◽  
P. Meister ◽  
M. Strobel ◽  
...  
Keyword(s):  
Laser Beam ◽  
Transmission System ◽  
Water Jet ◽  
Jet Stream ◽  
Yag Laser

Numerical simulation of water jet–guided laser cutting of carbon fiber–reinforced plastics

2018 ◽  
Vol 233 (10) ◽  
pp. 2023-2032 ◽  
Author(s):  
Dong Sun ◽  
Fuzhu Han ◽  
Weisheng Ying
Keyword(s):  
Carbon Fiber ◽  
Laser Beam ◽  
Element Model ◽  
Water Jet ◽  
Fiber Reinforced ◽  
Laser Beam Machining ◽  
Carbon Fiber Reinforced Plastics ◽  
Reinforced Plastics ◽  
Fiber Reinforced Plastics ◽  
Carbon Fiber Reinforced

Carbon fiber–reinforced plastics are now widely used in various industries because of its excellent properties. Although milling and drilling are the dominating processing methods for carbon fiber–reinforced plastics at present, laser beam machining, as a wear-free, contactless and flexible process, is considered a promising alternative method. However, the thermal damage is one of the most important issues for laser beam machining of carbon fiber–reinforced plastics because of the significant difference in thermal properties of carbon fiber and matrix. Water jet–guided laser technique has been proved an effective technique to reduce heat damage. Nevertheless, there are few studies about carbon fiber–reinforced plastics processing with water jet–guided laser to date. It is important to understand the mechanism of interaction between water jet–guided laser and carbon fiber–reinforced plastics. Hence, a three-dimensional finite element model was developed to investigate the transient thermal process. The influence of scanning speed on the surface appearance, heat-affected zone and shape of the cross section was illustrated. Experiments with same process parameters were conducted to validate the model. Based on the finite element model and experiments, the mechanism of material removal was explained. The epoxy is considered to be removed once it reaches the melting point and the carbon fiber is removed at the sublimation temperature. Because of the strong cooling effect of water jet, there is nearly no heat accumulation between pulses, leading to the constant heat-affected zone width at different scanning speed. The kerf sidewall is relatively vertical due to the homogeneous power distribution in water jet. The results demonstrate that water jet–guided laser cutting of carbon fiber–reinforced plastics has some advantages than traditional laser beam machining and is a potential processing method for carbon fiber–reinforced plastics.

Two-photon excitation microscopy in cellular biophysics

1995 ◽  
Vol 53 ◽  
pp. 62-63
Author(s):  
David W. Piston ◽  
Brian D. Bennett ◽  
Robert G. Summers
Keyword(s):  
Confocal Microscopy ◽  
Laser Beam ◽  
Duty Cycle ◽  
Excited Electronic State ◽  
Input Power ◽  
Two Photon ◽  
Simultaneous Absorption ◽  
Photon Excitation ◽  
Very High ◽  
Two Photon Excitation

Two-photon excitation microscopy (TPEM) provides attractive advantages over confocal microscopy for three-dimensionally resolved fluorescence imaging and photochemistry. Two-photon excitation arises from the simultaneous absorption of two photons in a single quantitized event whose probability is proportional to the square of the instantaneous intensity. For example, two red photons can cause the transition to an excited electronic state normally reached by absorption in the ultraviolet. In practice, two-photon excitation is made possible by the very high local instantaneous intensity provided by a combination of diffraction-limited focusing of a single laser beam in the microscope and the temporal concentration of 100 femtosecond pulses generated by a mode-locked laser. Resultant peak excitation intensities are 106 times greater than the CW intensities used in confocal microscopy, but the pulse duty cycle of 10-5 maintains the average input power on the order of 10 mW, only slightly greater than the power normally used in confocal microscopy.

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