Fiber lasers and amplifiers: an ultrafast performance evolution.
TL;DR: Fiber lasers are entering the realm of kilowatt powers in continuous as well as in pulse operation with diffraction-limited beam quality, and this power evolution is reviewed.
Abstract: The first rare-earth-doped fiber lasers were operated in the early sixties and produced a few milliwatts at a wavelength around 1 μm. For the next several decades, fiber lasers were little more than a low-power laboratory curiosity. Recently, however, fiber lasers are entering the realm of kilowatt powers in continuous as well as in pulse operation with diffraction-limited beam quality. In this article we review this power evolution.
Citations
More filters
TL;DR: In this paper, a review of the characteristics of ultrafast laser processing and the recent advancements and applications of both surface and volume processing is presented, and a summary of the technology with future outlooks are also given.
Abstract: The unique characteristics of ultrafast lasers, such as picosecond and femtosecond lasers, have opened up new avenues in materials processing that employ ultrashort pulse widths and extremely high peak intensities. Thus, ultrafast lasers are currently used widely for both fundamental research and practical applications. This review describes the characteristics of ultrafast laser processing and the recent advancements and applications of both surface and volume processing. Surface processing includes micromachining, micro- and nanostructuring, and nanoablation, while volume processing includes two-photon polymerization and three-dimensional (3D) processing within transparent materials. Commercial and industrial applications of ultrafast laser processing are also introduced, and a summary of the technology with future outlooks are also given. Scientists in Asia have reviewed the role of ultrafast lasers in materials processing. Koji Sugioka from RIKEN in Japan and Ya Cheng from the Shanghai Institute of Optics and Fine Mechanics in China describe how femtosecond and picosecond lasers can be used to perform useful tasks in both surface and volume processing. Such lasers can cut, drill and ablate a variety of materials with high precision, including metals, semiconductors, ceramics and glasses. They can also polymerize organic materials that contain a suitable photosensitizer and can three-dimensionally process inside transparent materials such as glass, and are already being used to fabricate medical stents, repair photomasks, drill ink-jet nozzles and pattern solar cells. The researchers also explain the characteristics of such lasers and the interaction of ultrashort, intense pulses of light with matter.
973 citations
TL;DR: In this article, the fundamental properties and latest developments in high-power fiber lasers are summarized and reviewed, focusing primarily on the most common fiber laser configurations and the associated cladding pumping issues.
Abstract: In this paper, we summarize the fundamental properties and review the latest developments in high power fiber lasers. The review is focused primarily on the most common fiber laser configurations and the associated cladding pumping issues. Special attention is placed on pump combination techniques and the parameters that affect the brightness enhancement observed in single-mode and multimode high power fiber lasers. The review includes the major limitations imposed by fiber nonlinearities and other parasitic effects, such as optical damage, transverse modal instabilities and photodarkening. Finally, the paper summarizes the power evolution in continuous-wave and pulsed ytterbium-doped fiber lasers and their impact on industrial applications.
812 citations
TL;DR: Lasers with ultrashort pulses are shown to be particularly useful tools for the production of nanocluster films and the important question of the film stoichiometry relative to that of the target will be thoroughly discussed in relation to the films reported in the literature.
Abstract: Laser ablation of dielectrics by ultrashort laser pulses is reviewed. The basic interaction between ultrashort light pulses and the dielectric material is described, and different approaches to the modeling of the femtosecond ablation dynamics are reviewed. Material excitation by ultrashort laser pulses is induced by a combination of strong-field excitation (multi-photon and tunnel excitation), collisional excitation (potentially leading to an avalanche process), and absorption in the plasma consisting of the electrons excited to the conduction band. It is discussed how these excitation processes can be described by various rate-equation models in combination with different descriptions of the excited electrons. The optical properties of the highly excited dielectric undergo a rapid change during the laser pulse, which must be included in a detailed modeling of the excitations. The material ejected from the dielectric following the femtosecond-laser excitation can potentially be used for thin-film deposition. The deposition rate is typically much smaller than that for nanosecond lasers, but film production by femtosecond lasers does possess several attractive features. First, the strong-field excitation makes it possible to produce films of materials that are transparent to the laser light. Second, the highly localized excitation reduces the emission of larger material particulates. Third, lasers with ultrashort pulses are shown to be particularly useful tools for the production of nanocluster films. The important question of the film stoichiometry relative to that of the target will be thoroughly discussed in relation to the films reported in the literature.
377 citations
TL;DR: Recent advances of high-power continuous wave, Q-switched, mode-locked, and single-frequency fiber lasers in the 1, 1.5, 2, and 3 μm regions and their applications in such areas as industry, medicine, research, defense, and security are addressed in detail.
Abstract: Fiber lasers have seen progressive developments in terms of spectral coverage and linewidth, output power, pulse energy, and ultrashort pulse width since the first demonstration of a glass fiber laser in 1964. Their applications have extended into a variety of fields accordingly. In this paper, the milestones of glass fiber laser development are briefly reviewed and recent advances of high-power continuous wave, Q-switched, mode-locked, and single-frequency fiber lasers in the 1, 1.5, 2, and 3 μm regions and their applications in such areas as industry, medicine, research, defense, and security are addressed in detail.
318 citations
TL;DR: In this article, the authors overview the field of the dispersion managed solitons starting from mathematical theories of Hamiltonian and dissipative systems and then discuss recent advances in practical implementation of this concept in fibre-optics and lasers.
262 citations
References
More filters
TL;DR: In this article, a periodic array of microscopic air holes that run along the entire fiber length are used to guide light by corralling it within a periodic arrays of microscopic holes.
Abstract: Photonic crystal fibers guide light by corralling it within a periodic array of microscopic air holes that run along the entire fiber length Largely through their ability to overcome the limitations of conventional fiber optics—for example, by permitting low-loss guidance of light in a hollow core—these fibers are proving to have a multitude of important technological and scientific applications spanning many disciplines The result has been a renaissance of interest in optical fibers and their uses
3,918 citations
TL;DR: Schawlow and Townes as discussed by the authors proposed a technique for the generation of very monochromatic radiation in the infra-red optical region of the spectrum using an alkali vapour as the active medium.
Abstract: Schawlow and Townes1 have proposed a technique for the generation of very monochromatic radiation in the infra-red optical region of the spectrum using an alkali vapour as the active medium. Javan2 and Sanders3 have discussed proposals involving electron-excited gaseous systems. In this laboratory an optical pumping technique has been successfully applied to a fluorescent solid resulting in the attainment of negative temperatures and stimulated optical emission at a wave-length of 6943 A. ; the active material used was ruby (chromium in corundum). After demonstration in 1954 of the 'maser' principle (microwave amplification by stimulated emission of radiation), systems were sought in which the effect occurred in the infrared and visible spectrum. This goal was reached in 1960 when Theodore Maiman achieved optical laser action in ruby.
3,893 citations
Journal Article•
TL;DR: Schawlow and Townes as discussed by the authors proposed a technique for the generation of very monochromatic radiation in the infra-red optical region of the spectrum using an alkali vapour as the active medium.
Abstract: Schawlow and Townes1 have proposed a technique for the generation of very monochromatic radiation in the infra-red optical region of the spectrum using an alkali vapour as the active medium. Javan2 and Sanders3 have discussed proposals involving electron-excited gaseous systems. In this laboratory an optical pumping technique has been successfully applied to a fluorescent solid resulting in the attainment of negative temperatures and stimulated optical emission at a wave-length of 6943 A. ; the active material used was ruby (chromium in corundum). After demonstration in 1954 of the 'maser' principle (microwave amplification by stimulated emission of radiation), systems were sought in which the effect occurred in the infrared and visible spectrum. This goal was reached in 1960 when Theodore Maiman achieved optical laser action in ruby.
3,646 citations
Book•
01 Jan 1958TL;DR: In this article, it was shown that by using a resonant cavity of centimeter dimensions, having many resonant modes, maser oscillation at these wavelengths can be achieved by pumping with reasonable amounts of incoherent light.
Abstract: The extension of maser techniques to the infrared and optical region is considered. It is shown that by using a resonant cavity of centimeter dimensions, having many resonant modes, maser oscillation at these wavelengths can be achieved by pumping with reasonable amounts of incoherent light. For wavelengths much shorter than those of the ultraviolet region, maser-type amplification appears to be quite impractical. Although use of a multimode cavity is suggested, a single mode may be selected by making only the end walls highly reflecting, and defining a suitably small angular aperture. Then extremely monochromatic and coherent light is produced. The design principles are illustrated by reference to a system using potassium vapor.
1,272 citations
Journal Article•
TL;DR: In this paper, the spectral distribution curve of temperature radiation was shown to be similar to the velocity distribution of the electromagnetic spectrum of a single photon, and the formal similarity of spectral distribution curves to Maxwell's velocity distribution curve was revealed.
Abstract: The formal similarity of the spectral distribution curve of temperature radiation to Maxwell’s velocity distribution curve is too striking to have remained hidden very long.
1,044 citations