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Advances in lasers and electro optics Part 18

Tham khảo tài liệu 'advances in lasers and electro optics part 18', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Application of Ultrafast Laser Optoperforation for Plant Pollen Walls and Endothelial Cell Membranes 831 Fig. 17. Representation of retinal segments irradiated with a single-shot ultrafast lasers. They were tentatively grouped into three types of lesions A. No change B. The ablations at the ILM and C. The optoperforation of blood vessel walls. The arrow head indicates the point of irradiations on the blood vessels. 0 20 40 60 80 100 2 Fluence J cm Fig. 18. Linear plot of the percent probability for inner limiting membrane ILM damage solid rectangles and vessel perforation solid circles as a function of the laser fluence. The ablation threshold fluence for ILM and blood vessels was found to be 2.19 1.08 J cm2 and 5.85 1.49 J cm2 respectively. With increasing fluence the percent probability of blood vessel perforation monotonically increases. The lines represent an extrapolation to determine the ablation thresholds for perforation of retinal primary blood vessels and for ILM damage of a porcine eye. 4.3 Discussion Recent development in advanced laser technology transiently facilitates to perform transaction ablation and coagulation of tissues via delivery of laser irradiation into a small focal volume are providing an attractive possibilities for new laser surgical technologies. The laser beam is a potential candidate that has already undergone a multi-center clinical 832 Advances in Lasers and Electro Optics trial to evaluate the feasibility for its use in vitreoretinal surgery Schastak et al. 2007 . Limited precision and significant damage by lasers with relative long pulse durations does not allow partial or selective tissue ablation with high precision. If such damage is to be overcome infrared laser sources such as CO2 Er YAG and Holmium YAG lasers have undergone several trials via optical fiber delivery in intraocular surgery. However apparent collateral damage to surrounding tissue due to significant thermal and shockwave effects have been reported Paula- Yu .