Proceedings ArticleDOI
Fabrication and replication of micro-optical structures for growth of GaN-based light emitting diodes
Gediminas Gervinskas,Gediminas Gervinskas,Gediminas Seniutinas,Gediminas Seniutinas,Anand Vijayakumar,Shanti Bhattacharya,Edgaras Jelmakas,A. Kadys,R. Tomašiūnas,Saulius Juodkazis,Saulius Juodkazis +10 more
- Vol. 8923, pp 682-691
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TLDR
In this paper, the exact shape of pattern milled into Al 2 O 3 was replicated into a 0.4mm-thick shim of Ni by electroplating.Abstract:
GaN light emitting diodes (LEDs) on sapphire substrates can be improved by micro-patterning substrate to perform epitaxial over-growth which drastically reduces defects' density in the light emitting region. We patterned Al 2 O 3 with focused ion beam and show a successful overgrowth of GaN. The exact shape of pattern milled into Al 2 O 3 was replicated into a 0.4-mm-thick shim of Ni by electroplating. The surface roughness of Ni was ~5:5 ±2 nm and is applicable for the most demanding replication of nano-rough surfaces. This technique can be used to replicate at micro-optical elements Fresnel-axicons defined by electron beam lithography made on sub-1 mm areas without stitching errors (Raith EBL). Shimming of macro-optical elements such as car back- reflectors is also demonstrated. Ni-shimming opens possibility to make replicas of nano-textured small and large area patterns and use them for thermal embossing and molding of optically-functionalized micro-fluidic chips and macro-optical elements.read more
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Journal ArticleDOI
Surface and bulk structuring of materials by ripples with long and short laser pulses: Recent advances
TL;DR: In this paper, a critical review of ripple formation mechanisms is presented, discussed, and formation conjectures are presented, and it is shown that formation of plasma at subcritical or critical densities on the surface and in the bulk specific to the high-intensity ultra-short laser pulses has to be considered to account for the experimental observations.
Journal ArticleDOI
All femtosecond optical pump and x-ray probe: holey-axicon for free electron lasers
Vijayakumar Anand,Jovan Maksimovic,Tomas Katkus,Soon Hock Ng,Orestas Ulčinas,Mindaugas Mikutis,Justas Baltrukonis,Antanas Urbas,Gintas Šlekys,H. Ogura,Daisuke Sagae,Tatiana Pikuz,Toshihiro Somekawa,Norimasa Ozaki,Arturas Vailionis,Gediminas Seniutinas,Vygantas Mizeikis,Karl Glazebrook,Jean P. Brodie,Paul R. Stoddart,Ludovic Rapp,Andrei Rode,Eugene G Gamaly,Saulius Juodkazis +23 more
TL;DR: In this paper, a co-axial pump (optical)-probe (x-rays) experimental concept and show performance of the optical component are presented and different realisations of optical pump are discussed.
Journal ArticleDOI
Imaging with diffractive axicons rapidly milled on sapphire by femtosecond laser ablation
Daniel Smith,Soon Hock Ng,Molong Han,Tomas Katkus,Vijayakumar Anand,Karl Glazebrook,Saulius Juodkazis,Saulius Juodkazis +7 more
TL;DR: In this article, a fundamental diffractive optical element, binary axicon-axicon with two phase or amplitude levels, has been designed in three configurations namely conventional axicon, photon sieve axicon (PSA) and sparse PSA and directly milled onto a sapphire substrate.
Posted Content
All femtosecond optical pump and X-ray probe: holey-axicon for free electron laser
Vijayakumar Anand,Jovan Maksimovic,Tomas Katkus,Soon Hock Ng,Orestas Ulčinas,Mindaugas Mikutis,Justas Baltrukonis,Antanas Urbas,Gintas Šlekys,H. Ogura,Daisuke Sagae,Tatiana Pikuz,Toshihiro Somekawa,Norimasa Ozaki,Arturas Vailionis,Gediminas Seniutinas,Vygantas Mizeikis,Karl Glazebrook,Jean P. Brodie,Paul R. Stoddart,Ludovic Rapp,Andrei Rode,Eugene G Gamaly,Saulius Juodkazis +23 more
TL;DR: In this paper, a co-axial pump (optical)-probe (X-rays) experimental concept and show performance of the optical component are presented. But the performance of optical pump is limited to the case of femtosecond X-ray free electron laser (FEL).
Posted ContentDOI
All Femtosecond Optical Pump and X-Ray Probe: Holey-Axicon for Free Electron Laser
Vijayakumar Anand,Jovan Maksimovic,Tomas Katkus,Soon Hock Ng,Orestas Ulčinas,Mindaugas Mikutis,Justas Baltrukonis,Antanas Urbas,Gintas Šlekys,H. Ogura,Daisuke Sagae,Tatiana Pikuz,Toshihiro Somekawa,Norimasa Ozaki,Arturas Vailionis,Gediminas Seniutinas,Vygantas Mizeikis,Karl Glazebrook,Jean P. Brodie,Paul R. Stoddart,Ludovic Rapp,Andrei Rode,Eugene G Gamaly,Saulius Juodkazis +23 more
TL;DR: In this paper, a co-axial pump (optical)-probe (X-rays) experimental concept and show performance of the optical component are presented. But the performance of optical pump is limited to the case of femtosecond X-ray free electron laser (FEL).
References
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Journal ArticleDOI
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Journal ArticleDOI
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Ričardas Buividas,Lorenzo Rosa,Remigijus Sliupas,Tadas Kudrius,Gintas Šlekys,V. V. Datsyuk,Saulius Juodkazis +6 more
TL;DR: The mechanism of the fine ripples, perpendicular to laser polarization, on the surface of (semi)transparent materials with period smaller than the vacuum wavelength, λ, of the incident radiation is proposed and experimentally validated.