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Date of Conference: 21–25 June 2015 Conference Name: 2015 European Conference on Lasers and Electro-Optics - European Quantum Electronics Conference Nanoscale periodic surface structures are of paramount importance in material science [1]. The recently demonstrated Nonlinear Laser Lithography (NLL) technique allows creating nanostructure arrays over indefinitely large surfaces with remarkable periodicity, not attainable by conventional laser induced periodic surface structure (LIPSS) methods [2]. Using NLL with linearly polarized femtosecond pulses, nanolines parallel to polarization emerge from initial surface roughness, and propagate on the surface as the laser beam is scanned. Here, we demonstrate that the final surface patterns depend not only on the polarization, but also on the surface morphology, which is controllable by introducing artificial defects. We use line defects as a control parameter to select a surface tiling from a set of available ones.

Date of Conference: 21–25 June 2015 Conference Name: 2015 European Conference on Lasers and Electro-Optics - European Quantum Electronics Conference Functional optical elements fabricated on silicon (Si) constitute fundamental building blocks of Si photonics [1]. For the fabrication of these elements, conventional lithography and etching techniques are used. In spite of the success of these techniques, a functional optical element embedded inside silicon simply does not exist. Here, we present a maskless, one-step laser writing technique for creating phase-type Fresnel zone plates in the bulk of Si. Due to their effectiveness over a broad spectra, Fresnel zone plates (FZPs) are widely used in various micro-imaging applications [2]. Similar lenses have been fabricated inside silica [3,4], but are limited to the transparency window of silica. The silicon counterpart of these elements have been impossible to fabricate so far. By exploiting nonlinear absorption within the focal volume of a tightly focused laser, we generated permanent refractive index changes in Si. The imprinted high-index contrast was then used to fabricate a FZP inside Si. This three dimensional (3D) method can allow for alignment-free multilens systems. Moreover, using silicon as the lens material is fully CMOS compatible and applicable to silicon integrated optics, including single and array detectors.

Date of Conference: 21–25 June 2015 Conference Name: 2015 European Conference on Lasers and Electro-Optics - European Quantum Electronics Conference Micromachining of silicon (Si) with lasers is being investigated since the 1970s [1]. So far, generation of controlled subsurface modification in the bulk of Si with high precision has not been achieved. This is highly desirable since successful integration of Si photonics and data transfer elements with conventional Si integrated circuits is proposed to lead to new generations of microprocessors [2,3]. Available techniques fabricate these optical and electronic elements on the top layer of the silicon-on-insulator platform. Despite the remarkable successes of conventional techniques, none of the available methods make use of the bulk of Si for positioning functional elements. Here, we report a method for photo-inducing deeply buried (down 1 mm) structures in Si wafers with pulsed infrared lasers. We demonstrate large aspect-ratio structures with 1-µm widths and long range order over millimetre scales. We further demonstrate multilevel spatial information encoding capabilities in subsurface barcodes.

Date of Conference: 21–25 June 2015 Conference Name: 2015 European Conference on Lasers and Electro-Optics - European Quantum Electronics Conference Laser induced periodic surface structures (LIPSS) had been observed just five years after the invention of laser [1]. Among the numerous LIPSS techniques none of them could maintain long-range order [2]. However, it has recently been demonstrated that long order periodic surface structures can be produced using nonlinear laser lithography (NLL) [3]. Here, we present a mathematical foundation for NLL.

Date of Conference: 21–25 June 2015 Conference Name: 2015 European Conference on Lasers and Electro-Optics - European Quantum Electronics Conference Femtosecond laser pulse sources have become increasingly popular in the last decade as a result of their practical features, such as insensitivity to environmental variations, versatile designs, high-power outputs. However, much of the progress is with non-integrated specialty fibers, which involve some compromise on these practical features. Monolithic fiber chirped pulse amplification (CPA) systems are very attractive for industrial and scientific applications due to the features such as compactness, reliability and robustness [1].