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The formation of these clusters would lead to some structural disorder and the observed glass-like thermal behaviour of the thermal conductivity. Modulated laser beam delivery is also an option. The way to achieve high output power is to combine several broad area emitters on a single chip as a linear bar or as a two-dimensional stack. Before sharing sensitive information, make sure you're on a federal government site. Side-pumping is another efficient option, to get more flexibility in the management of power and gain-scaling compromises while minimising the limitations due to nonlinear effects. Yan, in Optical Fiber Telecommunications (Third Edition), Volume A, 1997. Meanwhile, the waveguide in the lateral direction (known as the ‘slow axis’) is large, and highly multimode. This explains why a number of highly efficient designs have been demonstrated with YAG and KGW–KYW-based materials, taking advantage of rather large cross-sections and of high doping capabilities. Recently, it has been demonstrated that strong Bragg gratings can be written in P-doped fibers sensitized by deuterium loading (Kitagawa et al. The brightness (B) of diode lasers can be enhanced by increasing optical output power (P) and decreasing M2 factor. R. Moncorgé, ... J.L. A 400 μs long burst of pulses then gets amplified in two Nd:YLF diode-side-pumped amplifier stages with 5 Hz repetition rate (Ross et al., 2003). A. Jolly, in Handbook of Solid-State Lasers, 2013. The material’s very low thickness, typically 100 to 300 μm, makes possible efficient and uniform back-side cooling throughout the whole cross-section of the laser beam. This technology has been thoroughly investigated in frame of a nationally funded German research project “Modular Diode Laser Systems”, which has ended with the end of year 2003 (Bachmann, 2003). Output spectrum of the quasi-continuous high-power linear laser bar(©JENOPTIK Laser GmbH). This high sensitivity is due to the resonance enhancement and the fourth-power frequency dependence of Raman scattering intensity in comparison with nonresonance long wavelength excitation. For many applications high-power CW output is the main requirement, although many applications necessitate additional features such as good beam quality, narrow spectral linewidth, and wavelength stability over a wide range of temperature. One such example is the photo-injector of the linear collider nuclear test facility at the European organization for nuclear research (CERN) (Petrarca et al., 2011). Since Raman scattering cross-section is the reciprocal of the fourth power of the wavelength, RR using 488 and 532 nm excitation wavelength gives almost seven and five times more intense Raman signal than using 785 nm excitation wavelength, respectively. Early studies of Resonance Raman effects used ultraviolet light excitation, usually at wavelengths below 300 nm. Because the Raman gain coefficient at 1320 cm− 1 in P-doped fiber increases with the P-dopant concentration, it is desirable to have a high delta value. %%EOF
Therefore, it has a lower selectivity of cancer of different grades and normal regions. The LLNL system for controlling high current laser diode arrays is a system that allows the compact and efficient operation of high peak power diode arrays. High power laser diodes for wavelengths shorter than 1.3 μm have been reported with CW output power as high as ~ 10 W CW [138,139] from 100 μm wide broad area stripes. The laser is mounted epi-side up for the measurement. A second problem arises when one considers that with existing PCE being so much larger than the load that the load and the PCE now be separated by long cables that do not lend themselves to high current pulse operation. The LLNL system for controlling high current laser diode arrays is an integrated system for meeting the needs of driving laser diode arrays in a DPSSL. The output spectrum can be tuned by temperature at a rate of about 0.3 nm/deg (Zory, 1993). It makes use of a very thin disk of Yb-doped material (Fig. 11.4. E. Hulicius, V. Kubeček, in Lasers for Medical Applications, 2013. The pump radiation is reflected once from the facet opposite to the pump face and the fundamental beam undergoes five passes through the gain sheet. A good example of power scalability has been presented by Hirano et al. While higher output power can be achieved by increasing the lateral dimension, this also results in significant degradation of the beam quality factor due to self-focusing nonlinearities and filamentation. An optical-to optical efficiency of 47% in fundamental mode with 16.7 W of the peak output power during quasi-cw operation has been achieved at the wavelength of 1053 nm by a pumping method that can be envisioned as a mix of side- and longitudinal pumping (Wetter et al., 2009; Deana and Wetter, 2012). High-power diode lasers generally come in the form of a linear array of emitters and are diffraction limited perpendicular to the array and highly multimode in the direction of the array. High-power diode laser systems based on broad-area FP lasers and bars have several advantages, such as high optical power, and efficiency, in addition to low cost and a small footprint. This direction is known as the ‘fast axis’, as the beam diverges very rapidly due to the small waveguide aperture. Another important parameter used in evaluating the beam quality of a laser is its M2 factor, which compares an arbitrary beam to a Gaussian beam of similar proportions. BPP is related to the beam étendue. The rapid degradation in pulsed output power shown in Figure 17.30 is attributed to catastrophic optical mirror damage (COD) and/or burnout of the p-side contact directly under the probe tip. (2000). For 1.5 μm, InGaAsP has reached pulsed output level of 16 W . In our previous research works, the VRR technique has been used on human brain (cerebrospinal fluids [CSF], living glioma [GBM] cells), breast, skin, GYN, GI, and artery (vulnerable atherosclerotic plaque detection and atherosclerotic abdominal aortic tissues) studies since 2011 [6,7,9,47,48,84,87].