tailieunhanh - Báo cáo hóa học: " Synthesis of Glass Nanofibers Using Femtosecond Laser Radiation Under Ambient Condition"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Synthesis of Glass Nanofibers Using Femtosecond Laser Radiation Under Ambient Condition | Nanoscale Res Lett 2009 4 1263-1266 DOI s11671-009-9390-y NANO EXPRESS Synthesis of Glass Nanofibers Using Femtosecond Laser Radiation Under Ambient Condition M. Sivakumar K. Venkatakrishnan B. Tan Received 29 May 2009 Accepted 3 July 2009 Published online 19 July 2009 to the authors 2009 Abstract We report the unique growth of nanofibers in silica and borosilicate glass using femtosecond laser radiation at 8 MHz repetition rate and a pulse width of 214 fs in air at atmospheric pressure. The nanofibers are grown perpendicular to the substrate surface from the molten material in laser-drilled microvias where they intertwine and bundle up above the surface. The fibers are few tens of nanometers in thickness and up to several millimeters in length. Further it is found that at some places nanoparticles are attached to the fiber surface along its length. Nanofiber growth is explained by the process of nanojets formed in the molten liquid due to pressure gradient induced from the laser pulses and subsequently drawn into fibers by the intense plasma pressure. The attachment of nanoparticles is due to the condensation of vapor in the plasma. Keywords Silica nanofibers Femtosecond laser ablation Nanostructuring Introduction Micro- and nanoscale photonic devices require miniaturized glass-based photonic components. In this context M. Sivakumar B. Tan El Department of Aerospace Engineering Ryerson University 350 Victoria Street Toronto ON M5B 2K3 Canada e-mail tanbo@ K. Venkatakrishnan Department of Mechanical and Industrial Engineering Ryerson University 350 Victoria Street Toronto ON M5B 2K3 Canada silica nanofibers have a great potential as low-loss waveguides for nano-optics and microphotonics applications. The large tensile strength of these fibers allows for the development of micro- and nanomechanical springs and levers 1 . Nanofibers can also be used as reinforcement for the fabrication of dental composites. Various techniques have been proposed for