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Ultrafast Fiber Lasers
Published in Iniewski Krzysztof, Integrated Microsystems, 2017
A fiber laser is a laser in which the active gain medium is an optical fiber doped with rare-earth elements such as erbium, ytterbium, neodymium, dysprosium, praseodymium, and thulium. Fiber nonlinearities, such as stimulated Raman scattering or four wave mixing, can also provide gain and thus serve in effect as gain media. Unlike most other types of lasers, the laser cavity in a fiber laser is constructed monolithically by fusion splicing the different types of fibers; most notably fiber Bragg gratings replace conventional dielectric mirrors to provide optical feedback. To pump fiber lasers, semiconductor laser diodes or other fiber lasers are used almost exclusively. Fiber lasers can have several-kilometers-long active regions and provide very high optical gain. They can support kilowatt level continuous output power because the fiber’s high surface area-to-volume ratio allows efficient cooling. The fiber waveguiding properties reduce or remove completely thermal distortion of the optical path, thus resulting in typically diffraction-limited high-quality optical beams. Fiber lasers also feature compact layout compared to rod or gas lasers of comparable power, as the fiber can be bent to small diameters and coiled. Other advantages include high vibrational stability, extended lifetime, and maintenance-free turnkey operation.
Application of Nonlinear Microscopy in Life Sciences
Published in Lingyan Shi, Robert R. Alfano, Deep Imaging in Tissue and Biomedical Materials, 2017
Zdenek Svindrych, Ammasi Periasamy
While wide tunability is a key benefit in a research environment, the complexity and price of these systems make fixed wavelength pulsed lasers a viable alternative in biological research. Fiber lasers (the fiber core, doped with fluorescent ions, is the gain medium, so high pump power can be maintained over extended length) are especially attractive for their ruggedness, reliability, and low price. As examples, Er-doped fiber lasers produce 1560 nm (780 nm after frequency doubling), 100 fs pulses; Yb-doped fiber lasers emit at 1040 nm. With these lasers, multiphoton imaging of some fluorescent proteins and SHG imaging are readily achievable [46].
Analysis of the vein wall destruction under endovenous laser ablation in an ex vivo model
Published in Journal of Cosmetic and Laser Therapy, 2021
Natalia Ignatieva, Olga Zakharkina, Alexander Kurkov, Maxim Molchanov, Konstantin Mazayshvili
To carry out the ex-vivo modeling of the EVLA procedure, a 5-cm-long vein segment was fixed under slight tension and placed in a plastic cylindrical container filled with a 0.15-M NaCl solution. Heparinized blood (about 0.5 ml) was injected into the vein lumen. Laser radiation was delivered via optical fiber whose bare tip was placed at the distal end of the vein fragment under study. Irradiation and 0.7-mm/s automatic fiber traction started simultaneously. An erbium-doped fiber laser 1.56 µm in wavelength (LS-1.56, IRE-POLUS, Russia), and a diode laser 0.97-µm in wavelength (LSP, IRE-POLUS, Russia) emitted in CW mode were used in the experiment. The laser radiation power was varied from 3 to 7 W for fiber laser 1.56 µm and from 8 to 13 W for diode laser 0.97-µm. The laser radiation power was measured with a UP12-H power meter (Gentec Electro-Optics).
Intervention of 3D printing in health care: transformation for sustainable development
Published in Expert Opinion on Drug Delivery, 2021
Sujit Kumar Debnath, Monalisha Debnath, Rohit Srivastava, Abdelwahab Omri
Laser-engineered net shaping (LENS) is also known as laser metal deposition (LMD), direct laser deposition (DLD), direct light fabrication (DLF), powder fusion welding (PFW), and laser deposition welding (LDW). A laser is employed to melt the powder using the cladding process. Rapid cooling in this process helps to generate fine-grained microstructure, high tensile strength, and high ductility [12]. There are generally three types of lasers (CO2, Nd, and fiber laser) and their selection influences the process, microstructure, and mechanical strength of the 3D printing product [40]. This LENS technique was also employed in the fabrication of Ti6Al4V implant material with improved surface-related properties [41]. Fabricated material demonstrated low cytotoxicity and well biocompatibility with human mesenchymal stem cells.
Efficacy and safety of 1927 nm fractional Thulium fiber laser for the treatment of melasma: a retrospective study of 100 patients
Published in Journal of Cosmetic and Laser Therapy, 2019
G. Kurmuş, A. Tatlıparmak, B. Aksoy, E. Koç, Z. Aşiran Serdar, C. Ergin
The major side effects of using lasers and light sources for the treatment of melasma include post-inflammatory hyperpigmentation (PIH) and recurrence (5). More recently, fractional lasers have been discovered as a better option than classical ablative lasers. The 1550 nm erbium doped fiber laser was the first generation of fractional lasers used for the treatment of melasma (4). Next, the 1927 nm Thulium fiber laser was introduced in 2009 for the treatment of hyperpigmentation. The thulium laser targets water instead of pigment molecules, and has less risk of PIH compared to traditional lasers. The 1927 nm wavelength delivers energy up to 200 µm into the papillary dermis. Therefore, it is generally used for epidermal lesions (3). However, the target of the 1927 nm thulium laser is the dermo-epidermal junction. In this study, we aimed to determine the efficacy and side effects of the 1927 nm Thulium fiber laser for the treatment of melasma.