Structural changes in fused silica after exposure to focused femtosecond laser pulses.
ABSTRACT Using in situ Raman scattering in a confocal microscopy setup, we have observed changes in the network structure of fused silica after modifying regions inside the glass with tightly focused 800-nm 130-fs laser pulses at fluences of 5-200 J cm(-2). The Raman spectra show a large increase in the peaks at 490 and 605cm(-1), owing to 4- and 3-membered ring structures in the silica network, indicating that densification occurs after exposure to the femtosecond laser pulses. The results are consistent with the formation of a localized plasma by the laser pulse and a subsequent microexplosion inside the glass.
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ABSTRACT: In this paper, we study the formation dynamics of ultra-short laser-induced micro dots under the surface of transparent materials. Laser-induced micro dots find their application in direct part marking, to address full life cycle traceability. We first demonstrate the possibility of direct laser part marking into the cladding of an optical fiber. Then, we monitor the laser affected zone with the help of a time-resolved phase contrast microscopy setup in a fused silica substrate. We show that the transient energy relaxation processes affect the host material over a region that exceeds the micro dot size by several micrometers.Lasers in Manufacturing Conference 2013; 01/2013
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ABSTRACT: This chapter covers the benefits and applications of ultrafast laser scanning microscopes from a biomedical perspective. The basic architecture of a laser microscope is discussed, including how to design a laser scanning system with lateral and axial control. Also investigated is the design of custom collection optics for optimizing the detection of emitted photons and maximizing that emitted fluorescence in the presence of photobleaching. In addition, this chapter addresses three techniques novel to the biomedical community. The first is the technique of temporal focusing and its application toward wide-field imaging and micromachining. Also investigated is the concept of photon counting in multiphoton microscopy and how this approach to imaging has become practical for everyday use. Finally, several different methods are revealed for implementing spectral imaging with a multiphoton microscope platform.Ultrafast Nonlinear Optics, Edited by Thomson, Robert and Leburn, Christopher and Reid, Derryck, 01/2013: chapter 11: pages 377; Springer International Publishing., ISBN: 9783319000169
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ABSTRACT: The dynamic nature of future optical networks requires high levels of integration, fast response times, and adaptability of the optical components. Laser micromachining circumvents the limitations of planar integration, allowing both three-dimensional integration and dense packaging of optical devices without alignment requirements. Femtosecond micromachining enables the analog of circuit printing by wiring light between photonic devices in addition to printing the actual photonic device into a single or multiple substrates. Femtosecond laser oscillator-only micromachining has several advantages over amplified femtosecond laser micromachining: easy control over the size of the structures without changing focusing, polarization-independent structures, lower initial investment cost and higher-speed manufacturing. In this paper we review recent results obtained in the field of femtosecond micromachining.