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Absorption Length
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Jonathan Lawrence – One of the best experts on this subject based on the ideXlab platform.
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An analysis of the beam interaction characteristics of selected lasers with an alpha-alumina bioceramic
Optics and Lasers in Engineering, 2004Co-Authors: Jonathan LawrenceAbstract:Abstract Certain differences between the interaction characteristics of a CO2 laser, a Nd:YAG laser and a high power diode laser with an alpha-alumina bioceramic have been investigated. For each laser the fluence threshold values at which significant material removal occurs were found graphically. Through the implementation of a derivative of Beer–Lambert’s law, the laser beam Absorption Lengths were calculated along with the thermal loading values. An examination of the laser-induced meltpool propagation in the alpha-alumina revealed good agreement with the Stefan solution to the heat diffusion equation for the lasers. Absorptivity measurements revealed that there was no correlation between the actual absorptivity of the alpha-alumina and the Absorption Length for each of the three lasers on account of the absorptivity measurements being similar for each laser. However, differences in the depth of melting experienced by the alpha-alumina meant that it is reasonable to assume that Absorption Length is the principal influence on the melt depth.
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Determination of the Absorption Length of CO2, Nd:YAG and high power diode laser radiation for a selected grouting material
Applied Surface Science, 2002Co-Authors: Jonathan Lawrence, K Minami, Roger E. Edwards, Andrew W GaleAbstract:Abstract The laser beam Absorption Lengths of CO2, Nd:YAG and a high power diode laser (HPDL) radiation for a newly developed SiO2/Al2O3-based tile grout have been determined through the application of Beer–Lambert’s law. The findings revealed marked differences in the Absorption Lengths despite the material having similar beam Absorption coefficients for the lasers. The Absorption Lengths for the SiO2/Al2O3-based tile grout for CO2, Nd:YAG and HPDL radiation were calculated as being 232±11, 193±4 and 183±8 μm , respectively. Moreover, this method of laser beam Absorption Length determination, which has hitherto been used predominantly with lasers operated in the pulsed mode, is shown to be valid for use with lasers operated in the continuous wave (CW) mode, depending upon the material being treated.
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Determination of the Absorption Length of CO2 and high power diode laser radiation for a high volume alumina-based refractory material
Applied Surface Science, 2000Co-Authors: Jonathan LawrenceAbstract:Abstract The laser beam Absorption Lengths of CO 2 (10.6 μm waveLength) and a high power diode laser (HPDL) (810 nm waveLength) radiation for an Al 2 O 3 /SiO 2 -based refractory have been determined through the application of Beer–Lambert’s law. The findings revealed marked differences in the Absorption Lengths despite the material having similar beam Absorption coefficients for both lasers. The Absorption Lengths for the Al 2 O 3 /SiO 2 -based refractory of CO 2 and a HPDL radiation were calculated as being 345±22 and 198±15 μm, respectively. Moreover, this method of laser beam Absorption Length determination, which has hitherto been used predominantly with lasers operated in the pulsed mode, is shown to be valid for use with lasers operated in the continuous wave (CW) mode, depending upon the material being treated.
Thomas F Deutsch – One of the best experts on this subject based on the ideXlab platform.
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co mgf 2 laser ablation of tissue effect of waveLength on ablation threshold and thermal damage
Conference on Lasers and Electro-Optics, 1991Co-Authors: Kevin T. Schomacker, Yacov Domankevitz, Thomas J Flotte, Thomas F DeutschAbstract:The waveLength dependence of the ablation threshold of a variety of tissues has been studied using a tunable pulsed Co:MgF2 laser in order to determine how closely it tracks the optical Absorption Length of water. The Co:MgF2 laser was optically pumped by a Nd:YAG laser emitting at 1.338 μm. Typical output energies were 70 μJ in a train of 2-JAS pulses approximately 100 μs long. The Co:MgF2 laser was tuned between 1.81 and 2.14 μm, a waveLength region in which the Absorption Length varies by a decade.
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co mgf2 laser ablation of tissue effect of waveLength on ablation threshold and thermal damage
Lasers in Surgery and Medicine, 1991Co-Authors: Kevin T. Schomacker, Yacov Domankevitz, Thomas J Flotte, Thomas F DeutschAbstract:Abstract The waveLength dependence of the ablation threshold of a variety of tissues has been studied by using a tunable pulsed Co:MgF2 laser to determine how closely it tracks the optical Absorption Length of water. The Co:MgF2 laser was tuned between 1.81 and 2.14 microns, a waveLength region in which the Absorption Length varies by a decade. For soft tissues the ablation threshold tracks the optical Absorption Length; for bone there is little waveLength dependence, consistent with the low water content of bone. Thermal damage vs. waveLength was also studied for cornea and bone. Thermal damage to cornea has a weak waveLength dependence, while that to bone shows little waveLength dependence. Framing-camera pictures of the ablation of both cornea and liver show explosive removal of material, but differ as to the nature of the explosion.
S.i. Najafi – One of the best experts on this subject based on the ideXlab platform.
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Length optimization of single-mode rare-earth doped waveguides using saturated Absorption
IEEE Photonics Technology Letters, 1995Co-Authors: V. Francois, T. Ohtsuki, N. Peyghambarian, S.i. NajafiAbstract:Absorption saturation was demonstrated to provide a high, uniform population inversion over a Length of waveguide longer than the material Absorption Length. The small signal gain was measured experimentally in single-mode waveguides, made by silver ion exchange, on a commercially available neodymium doped glass. The ratio of the excited states was calculated as a function of waveguide Length and was shown to be a convenient criteria to determine the optimum device Length.