Journal of Laser Applications 

About: Journal of Laser Applications is an academic journal published by Laser Institute of America. The journal publishes majorly in the area(s): Laser & Laser beam welding. It has an ISSN identifier of 1042-346X. Over the lifetime, 1718 publications have been published receiving 24963 citations.

Femtosecond laser-induced periodic surface structures

Abstract: The formation of laser-induced periodic surface structures (LIPSS) in different materials (metals, semiconductors, and dielectrics) upon irradiation with linearly polarized fs-laser pulses (τ ∼ 30–150 fs, λ ∼ 800 nm) in air environment is studied experimentally and theoretically. In metals, predominantly low-spatial-frequency-LIPSS with periods close to the laser wavelength λ are observed perpendicular to the polarization. Under specific irradiation conditions, high-spatial-frequency-LIPSS with sub-100-nm spatial periods (∼λ/10) can be generated. For semiconductors, the impact of transient changes of the optical properties to the LIPSS periods is analyzed theoretically and experimentally. In dielectrics, the importance of transient excitation stages in the LIPSS formation is demonstrated experimentally using (multiple) double-fs-laser-pulse irradiation sequences. A characteristic decrease of the LIPSS periods is observed for double-pulse delays of less than 2 ps.

Design guidelines for laser additive manufacturing of lightweight structures in TiAl6V4

Abstract: Today, laser additive manufacturing (LAM) is used in more and more industrial applications. Due to a new freedom in design it offers a high potential for weight saving in lightweight applications, e.g., in the aerospace industry. However, most design engineers are used to design parts for conventional manufacturing methods, such as milling and casting, and often only have limited experience in designing products for additive manufacturing. The absence of comprehensive design guidelines is therefore limiting the further usage and distribution of LAM. In this paper, experimental investigations on the influence of part position and orientation on the dimension accuracy and surface quality are presented. Typical basic shapes used in lightweight design have been identified and built in LAM. Thin walls, bars, and bore holes with varying diameters were built in different orientations to determine the process limits. From the results of the experiments, comprehensive design guidelines for lightweight structures were derived in a catalog according to DIN 2222 and are presented in detail. For each structure a favorable and an unfavorable example is shown, the underlying process restrictions are mentioned and further recommendations are given.

A review of ultrashort pulsed laser ablation of materials

Abstract: The use of ultrashort pulsed lasers in materials processing is an emerging technology. These lasers have the capability to ablate materials precisely with little or no collateral damage, even with materials that are impervious to laser energy from conventional pulsed lasers. The extreme intensities and short timescale at which ultrashort pulsed lasers operate differentiate them from other lasers. The means of ultrashort pulsed laser generation is discussed; included are a survey of pulse compressor techniques with solid state lasers and a brief discussion of excimer-dye lasers. This is followed by a discussion of specific examples of ultrashort pulsed machining of specific materials, along with mechanistic details. Optical breakdown mechanisms, including electron avalanche ionization and multiphoton absorption are discussed. It is shown that as pulse width increases and intensity decreases, laser damage becomes a stochastic process in which the ultrashort pulsed, high intensity light causes optical breakd...

A procedure for multiple-pulse maximum permissible exposure determination under the Z136.1-2000 American National Standard for Safe Use of Lasers

Abstract: The current national consensus standard for laser safety in the United States is the American National Standard for Safe Use of Lasers (ANSI Z136.1). Over the past few years, a comprehensive rewrite of this standard has been conducted. The updated version of the standard (Z136.1-2000) incorporates a wealth of new bioeffects data and establishes a number of new maximum permissible exposure (MPE) limits for laser safety. The updated standard also includes new procedures for the computation of MPE values, which must be understood by health physicists, laser safety officers, and others in the field of occupational safety. Here we present the first in a series of tutorial articles to clarify laser safety analysis procedures under this new standard. This article deals with the proper application of three rules for determining the appropriate MPE values for repetitively pulsed lasers or repeated exposures from laser beams.

Physics and applications of laser-shock processing

Abstract: The first part of this article presents a review of the main process parameters controlling pressure generation in a confined mode The effect of laser intensity, target material, laser pulse duration, and laser wavelength are, therefore, discussed An optimized process can then be defined The second part of this article deals with the surface modifications induced by laser-shock processing The generation of residual compressive stresses is then highlighted Finally, in the third part, the interest of laser-shock processing is discussed for several typical applications A conclusion will present the future trends of this technique