Published by De Gruyter

Volume 1 Issue 5

Issue of Advanced Optical Technologies

Contents
Journal Overview

Masthead

Publicly Available October 10, 2012

Editorial

Publicly Available October 10, 2012

Optics for laser material processing

Michael Pfeffer

Page range: 343-344

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Abstract

No abstract available.

Views

Publicly Available October 10, 2012

Laser materials processing market reaches record high

Arnold Mayer

Page range: 345-348

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Abstract

No abstract available.

Community

Publicly Available October 10, 2012

Female power in visual and physiological optics: both EOS student awards go to women

Page range: 349-350

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Abstract

No abstract available.

Publicly Available October 10, 2012

Abstract

No abstract available.

Topical Issue: Optics for material processing

Tutorial

Publicly Available October 10, 2012

A tutorial on optics for ultrafast laser materials processing: basic microprocessing system to beam shaping and advanced focusing methods

Koji Sugioka, Ya Cheng

Page range: 353-364

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Abstract

Ultrafast lasers have excellent characteristics for materials processing in terms of precision and quality. This tutorial paper introduces the basic concepts of ultrafast laser materials processing and the structure and key components of typical ultrafast laser microprocessing systems. The emphasis is on the pulse-shaping devices and systems for controlling and manipulating the spatial, temporal, and polarization properties of focused femtosecond laser pulses.

Review Article

Publicly Available October 10, 2012

Development of a hollow laser beam for micromachining

Erkan Demirci, Christian Nölke, Stefan Kaierle, Paolo Matteazzi

Page range: 365-370

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Abstract

Current laser cladding technologies have limited resolutions of about 50 μm. A new solution has been developed within the project ‘Nanomicro’ to improve the spatial resolution. The ‘micro hollow laser beam system’ and a deposition system for highly focused metal micropowders are innovative parts within a high-precision 3D micromanufacturing laser cladding platform. We demonstrate, here, a new hollow laser sintering concept that is aiming on more efficient laser cladding and manufacturing of highly precise and functional parts in the range of a few microns.

Research Articles

Publicly Available October 10, 2012

The design of f-θ-lenses for use in laser machining of glass

Leo H.J.F. Beckmann

Page range: 371-380

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Abstract

At high power densities in excess of, say, 10 9 W/cm 2 , such as may be created by focusing pulsed laser radiation of nanosecond pulse duration, optical glass is no longer transparent but absorbs the radiant power, resulting in stress and physical damage (cracks). While this is intended for certain techniques of machining glass and other normally transparent materials, secondary foci or ‘ghost images’ inside the focusing optics may also exceed the threshold for absorption and thereby cause damage to lenses if such ghost images fall inside an optical element. When designing optics for laser machining of glass, it is therefore important to control the formation of ghost images and to ensure that they are located outside all lens elements. This dominates the design process for such optical systems.

Publicly Available October 10, 2012

Applications of sub-wavelength grating mirrors in high-power lasers

Marwan Abdou Ahmed, Martin Rumpel, Andreas Voss, Thomas Graf

Page range: 381-388

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Abstract

A grating waveguide mirror (GWM) results from the combination of a waveguide and a sub-wavelength grating which lead, for given incidence conditions, to polarization and or wavelength filtering. In the present paper, we report on the application of such elements for the selection of the polarization (linear, radial, or azimuthal) as well as the narrowing, stabilizing and tuning of the emission spectrum of high-power lasers. Using a leaky-mode circular GWM, beams with radial and azimuthal polarization with output powers of up to 275 W and 145 W, respectively, could be extracted from a Yb:YAG thin-disk with optical efficiencies of 52.5% and 43%, respectively. In both cases, the GWM was composed of a highly reflective (HR) mirror and a sub-wavelength grating as the end-mirror of the resonator. Using a leaky-mode linear GWM operating under Littrow condition, beams with linear polarization and a narrow spectral bandwidth were obtained from a Yb:YAG thin-disk laser. In multimode operation, an output power of 325 W was achieved at an optical efficiency of 53.5%. In near-fundamental mode operation, 110 W was extracted at an optical efficiency of 36.2%. In this latter case, the spectral bandwidth was measured to be around 25 pm. Moreover, continuous wavelength tuning from 1007 to 1053 nm was demonstrated with our device.

Publicly Available October 10, 2012

Optical components and optical systems for VCSEL diode laser systems

Stephan Gronenborn, Michael Miller, Gero Heusler, Holger Mönch

Page range: 389-396

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Abstract

High power vertical-cavity surface-emitting laser (VCSEL) arrays can be used as a versatile illumination and heating source. They are widely scalable in power and offer a robust and economic solution for many new applications with moderate brightness requirements. The use of VCSEL arrays for high power laser diode applications enables multiple benefits: full wafer level production of VCSELs including combination with micro-optics; assembly technologies allowing large synergy with LED assembly thus profiting from the fast development in solid state lighting; outstanding reliability and a modular approach on all levels. With the use of μ-lenses, the described optical principle of near field imaging and superpositioning of many thousands of VCSELs gives perfect control over intensity distribution and is inherently robust. With a slightly modified approach, lines of any desired length can be built from modules of 1-cm length and are therefore scalable for a wide range of applications.

Letter

Publicly Available October 10, 2012

Annular beam shaping system for advanced 3D laser brazing

Oliver Pütsch, Jochen Stollenwerk, Markus Kogel-Hollacher, Martin Traub

Page range: 397-402

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Abstract

As laser brazing benefits from advantages such as smooth joints and small heat-affected zones, it has become established as a joining technology that is widely used in the automotive industry. With the processing of complex-shaped geometries, recent developed brazing heads suffer, however, from the need for continuous reorientation of the optical system and/or limited accessibility due to lateral wire feeding. This motivates the development of a laser brazing head with coaxial wire feeding and enhanced functionality. An optical system is designed that allows to generate an annular intensity distribution in the working zone. The utilization of complex optical components avoids obscuration of the optical path by the wire feeding. The new design overcomes the disadvantages of the state-of-the-art brazing heads with lateral wire feeding and benefits from the independence of direction while processing complex geometries. To increase the robustness of the brazing process, the beam path also includes a seam tracking system, leading to a more challenging design of the whole optical train. This paper mainly discusses the concept and the optical design of the coaxial brazing head, and also presents the results obtained with a prototype and selected application results.

About this journal

Objective

Advanced Optical Technologies is a strictly peer-reviewed scientific journal. The major aim of Advanced Optical Technologies is to publish recent progress in the fields of optical design, optical engineering, and optical manufacturing. Advanced Optical Technologies has a main focus on applied research and addresses scientists as well as experts in industrial research and development.

Advanced Optical Technologies partners with the European Optical Society (EOS). All its 4.500+ members have free online access to the journal through their EOS member account.

Topics

Optical design
Lithography
Opto-mechanical engineering
Illumination and lighting technology
Precision fabrication
Image sensor devices
Optical materials (polymer based, inorganic, crystalline/amorphous)
Optical instruments in life science (biology, medicine, laboratories)
Optical metrology
Optics in aerospace/defense
Simulation, interdisciplinary
Optics for astronomy
Standards
Consumer optics
Optical coatings

Article formats
Tutorial, Review Article, Research Article, Letter, Short Communication, Views

> Information on submission process

Volume 1 Issue 5

Issue of Advanced Optical Technologies

Masthead

Optics for laser material processing

Abstract

Laser materials processing market reaches record high

Abstract

Female power in visual and physiological optics: both EOS student awards go to women

Abstract

Conference Calendar

Abstract

A tutorial on optics for ultrafast laser materials processing: basic microprocessing system to beam shaping and advanced focusing methods

Abstract

Development of a hollow laser beam for micromachining

Abstract

The design of f-θ-lenses for use in laser machining of glass

Abstract

Applications of sub-wavelength grating mirrors in high-power lasers

Abstract

Optical components and optical systems for VCSEL diode laser systems

Abstract

Annular beam shaping system for advanced 3D laser brazing

Abstract