Dr. Dimitris Karnakis Profile

Dr. Dimitris Karnakis

Technical Manager R&D Projects at Oxford Lasers Ltd

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Publications (12)

Proceedings Article | 20 June 2024 Presentation

Why use ultrashort pulsed lasers for laser microwelding of dissimilar materials

Dimitris Karnakis, Etienne Pelletier

Proceedings Volume PC13005, PC1300507 (2024) https://doi.org/10.1117/12.3016744

KEYWORDS: Pulsed laser operation, Laser bonding, Glasses, Silicon, Metals, Ceramics, Anodic bonding, Sapphire, Vibration, Ultrafast phenomena

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Proceedings Article | 20 September 2020 Presentation

Industrial-grade custom tool for ultrafast laser microwelding of dissimilar materials (glass to metal)

Dimitris Karnakis, Etienne Pelletier, Daniel Arnaldo del Cerro, Riccardo Geremia, David Grant

Proceedings Volume 11540, 1154013 (2020) https://doi.org/10.1117/12.2574007

KEYWORDS: Glasses, Metals, Ultrafast lasers, Optics manufacturing, Manufacturing, Aluminum, Defense and security, Adhesives, Electro optics, Silica

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Bonding of metals to transparent materials (glasses, crystals, etc.) is commonly used for several applications in modern defence manufacturing including for hermetic sealing and precision optics mounting. Common methods include the use of organic adhesives or glass frit interlayers as well as diffusion, anodic and arc bonding. Such techniques are typically esoteric and operator skill dependent. They can introduce large heat input risking the device integrity or are subject to post-process creep and volatile components outgassing, which can lead to contamination of optical surfaces and subsequent device degradation. Adhesives in particular are not truly hermetic and so are largely unsuitable for electro-optics and miniature lasers fabrication. They are sensitive to environment, swelling in the presence of moisture, softening at high temperatures or becoming stiff and brittle at low temperatures. All of the above are highly undesirable. Apart from limiting the range of material combinations possible to join, such bonding often ends up as a lengthy, error prone manufacturing step. This explains why so many manufacturers would like to replace such bonding with a more deterministic process. Recently [1] direct microwelding of glass to metal (BK7 and fused silica to Al) has been demonstrated utilising ultrafast lasers which offer non-contact fabrication with high precision, high process speed and very small heat affected zones. In this paper we will showcase a purpose-built ultrafast laser prototype for laser microwelding of 10-20mm thick bulk optics (lenses, waveplates, prisms) to flat aluminium or stainless steel mounts with sufficient bond strength for use in advanced manufacturing for defence applications. Various demonstrated case studies in aerospace electro-optics assemblies and flexible electronics hermetic sealing for device encapsulation will be discussed in detail including bond strength shear test characterisation, thermal and vibration cycling. This laser microwelding tool is suitable for early adoption of this microwelding technology and for process development in several other optical material welding applications (e.g. glass to silicon; glass to ceramic, Nd:YAG to metal, etc.).

Proceedings Article | 11 March 2020 Presentation + Paper

High speed laser printing and sintering of flexible RFID antennas and fingerprint sensors

Ioannis Theodorakos, Filimon Zacharatos, Marina Makrygianni, Agamemnon Kalaitzis, Olga Koritsoglou, Jonathan Ankri, Arye Schwarzbaum, Alon Melamed, Merijn Giesbers, Gari Arutinov, Simon Tuohi, Daniel Arnaldo, Nuno Braz, Riccardo Geremia, Dimitris Karnakis, Semyon Melamed, Ayala Kabla, Fernando De la Vega, Darshana Kariyapperuma, Brian Cobb, Richard Price, Patrick Too, Shane Norval, Ioanna Zergioti

Proceedings Volume 11267, 1126709 (2020) https://doi.org/10.1117/12.2561050

KEYWORDS: Printing, Nonimpact printing, Nanoparticles, Sensors, Silver, Antennas, Additive manufacturing, Laser sintering, Receivers, Metals

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Proceedings Article | 1 July 2015 Paper

Laser surface texturing of cast iron steel: dramatic edge burr reduction and high speed process optimisation for industrial production using DPSS picosecond lasers

David Bruneel, Andrew Kearsley, Dimitris Karnakis

Proceedings Volume 9657, 96570G (2015) https://doi.org/10.1117/12.2176204

KEYWORDS: Iron, Diode pumped solid state lasers, Picosecond phenomena, Pulsed laser operation, Laser processing, Interfaces, Etching, Laser optics, Laser ablation, Manufacturing

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Proceedings Article | 1 July 2015 Paper

The effect of laser pulse duration and beam shape on the selective removal of novel thin film layers for flexible electronic devices

C. Moorhouse, D. Karnakis, C. Kapnopoulos, A. Laskarakis, S. Logothetidis, G. Antonopoulos, E. Mekeridis

Proceedings Volume 9657, 96570E (2015) https://doi.org/10.1117/12.2175501

KEYWORDS: Thin films, Pulsed laser operation, Thin film devices, Positron emission tomography, Optical lithography, Glasses, Picosecond phenomena, Zinc oxide, Silicon, Semiconductor lasers

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Proceedings Article | 4 March 2015 Paper

Laser patterning for reel-to-reel production of organic photovoltaic (OPV) devices

C. Moorhouse, D. Karnakis, A. Kearsley, C. Kapnopoulos, Argiris Laskarakis, S. Logothetidis, E. Mekeridis

Proceedings Volume 9350, 93500Q (2015) https://doi.org/10.1117/12.2077488

KEYWORDS: Optical lithography, Thin films, Ultrafast lasers, Picosecond phenomena, Positron emission tomography, Organic photovoltaics, Pulsed laser operation, Absorption, Silver, Infrared lasers

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Proceedings Article | 15 March 2013 Paper

Ultrafast laser trimming for reduced device leakage in high performance OTFT semiconductors for flexible displays

Dimitris Karnakis, Michael Cooke, Y. Chan, Simon Ogier

Proceedings Volume 8608, 86080D (2013) https://doi.org/10.1117/12.2004007

KEYWORDS: Gold, Laser ablation, Glasses, Optical lithography, Flexible displays, Metals, Laser damage threshold, Etching, Pulsed laser operation, Semiconductors

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Proceedings Article | 13 March 2013 Paper

Maskless selective laser patterning of PEDOT:PSS on barrier/foil for organic electronics applications

Dimitris Karnakis, Tim Stephens, Gregoire Chabrol

Proceedings Volume 8607, 860711 (2013) https://doi.org/10.1117/12.2001670

KEYWORDS: Laser ablation, Pulsed laser operation, Optical lithography, Metals, Laser applications, Organic light emitting diodes, Diode pumped solid state lasers, Organic electronics, Picosecond phenomena, Absorption

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Proceedings Article | 1 March 2006 Paper

High quality laser milling of ceramics, dielectrics and metals using nanosecond and picosecond lasers

Dimitris Karnakis, Graham Rutterford, Martyn Knowles, Todor Dobrev, Petko Petkov, Stefan Dimov

Proceedings Volume 6106, 610604 (2006) https://doi.org/10.1117/12.645711

KEYWORDS: Surface roughness, Copper vapor lasers, Micro cutting, Picosecond phenomena, Metals, Pulsed laser operation, Silica, Ceramics, Dielectrics, Radium

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Proceedings Article | 22 January 2005 Paper

Comparison of glass processing using high-repetition femtosecond (800 nm) and UV (255 nm) nanosecond pulsed lasers

Dimitris Karnakis, Martyn Knowles, Kevin Alty, Martin Schlaf, Howard Snelling

Proceedings Volume 5718, (2005) https://doi.org/10.1117/12.588194

KEYWORDS: Glasses, Pulsed laser operation, Microfluidics, Femtosecond phenomena, Copper vapor lasers, Laser processing, Borosilicate glass, Ultraviolet radiation, Laser glasses, Micromachining

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Proceedings Article | 21 June 2004 Paper

High-throughput scribing for the manufacture of LED components

Dimitris Karnakis, Elizabeth Illy, Martyn Knowles, Erdan Gu, Martin Dawson

Proceedings Volume 5366, (2004) https://doi.org/10.1117/12.531685

KEYWORDS: Sapphire, Light emitting diodes, Laser cutting, Pulsed laser operation, Manufacturing, Gallium nitride, Ultraviolet radiation, Semiconducting wafers, Photonics, Sapphire lasers

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Proceedings Article | 30 October 2001 Paper

Microhole drilling using reshaped pulsed Gaussian laser beams

Dimitris Karnakis, Jim Fieret, Phil Rumsby, Malcolm Gower

Proceedings Volume 4443, (2001) https://doi.org/10.1117/12.446744

KEYWORDS: Laser drilling, Gaussian beams, Telescopes, Nd:YAG lasers, Polymers, Silicon, Ray tracing, Ceramics, Monochromatic aberrations, Beam analyzers

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Showing 5 of 12 publications

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