Monthly Archives: February 2011

Comparison of 1 Micron Transmissive Optical Materials for High Power Lasers

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By: Steve Rummel, Gary Herrit, Alan Hedges

II-VI Infrared

One of the problems that high power fiber, direct-diode, and disk laser users experience is thermal lensing of their beam delivery optics and debris windows. This is placing increased demands on the optics used in 1 micron laser beam delivery systems. Direct-diode lasers, meanwhile, continue to show improved beam quality and may eventually be used for industrial metal cutting applications, placing increased demands on the optics used in these lasers.

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Novel Processes in Laser Micro-fabrication and Micro-joining

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By: Kazuyoshi Itoh, YasuyukiOzeki

Department of Material and Life Science, Osaka University

Focused ultrafast laser pulses can cause a variety of the structural modifications including void, damage, refractive index (RI) change, and crack, depending on materials and irradiation conditions such as pulse energy, pulse width and numerical aperture (NA) of the focusing lens. Among these modifications, the RI change is interesting especially for the application to micro-fabrication of 3D photonic devices inside glass. The RI change occurs as a result of localized melting and rapid re-solidification. Fused silica shows positive RI change, allowing us to fabricate waveguides in glass. Other devices such as diffractive optical elements (DOE’s) can be fabricated regardless of the sign of RI change. We review this technique focusing on the fabrication of photonic devices (see Fig. 1).

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Micro-Hole Drilling on Cemented Tungsten Carbide by Ultra Short Laser Pulses

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By: Khai Pham Xuan, Kazuya Saginawa, Rie Tanabe, Yoshiro Ito

Department of Mechanical Engineering, Nagaoka University of Technology

Recently, high precision molds for small products are being highly required in many industrial applications, especially in information communication technology. Mold materials with high hardness, such like cemented tungsten carbide (WC-Co), are difficult to machine by classical chip-removal techniques and the electrical discharge machining (EDM) is mainly used technology in microfabrication of hard materials. Even though the accuracy of EDM is fairly high K.H. Ho and S.T. Newmann, State of the art electrical discharge machining (EDM), it has several drawbacks  such as slow machining rate and the additional time and cost needed for polishing and finishing processes. Recently, laser machining becomes an effective technique for machining of hard materials. Many experimental results show that short pulse laser machining allows removal of very small amount of material with little heat affected zone compared with nanosecond or longer pulse lasers.

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Wide Operational Range Pulsed Fiber Laser for Processing Thin Film Photovoltaic Panels

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By: Shinobu Tamaoki

Sumitomo Electric Inc.

Pulse fiber lasers (PFL) have become widely popular for micro-machining applications due to their many benefits, such as the high beam quality, compactness, high wall-plug efficiency, and reliability. MOPA (Master Oscillator Power Amplifier) architectures, which provide temporal pulse shape control, are particularly interesting.

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Surface Preparation for Shipbuilding Using a Pulsed High-Power Fibre Laser

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By: T. J. Kwee, G. X. Chen, N. R. Lei, K. P. Tan, Y. S. Choo, M. H. Hong

Centre of Innovation (Marine & Offshore Technology)
Faculty of Engineering, National University of Singapore

Ships play a significant role in our life by carrying about 90% of the world’s intercontinental cargo. But the service condition of ships in the seawater is severely corrosive. It often costs billions of dollars on maintenance, repair, and corrosion-related down time of ships. Ships require the best possible paint protection to extend their operating life and to save money.

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