Optical coherence tomography for process control of laser micromachining

Laser-Laboratorium Göttingen e.V., Hans-Adolf-Krebs-Weg 1, D-37077 Göttingen, Germany.
The Review of scientific instruments (Impact Factor: 1.58). 03/2010; 81(3):033705. DOI: 10.1063/1.3356080
Source: PubMed

ABSTRACT In situ surface imaging for nondestructive evaluation (NDE) by optical coherence tomography (OCT) before, during, and after ablative laser processing is presented. Furthermore, it is shown that the ability of in situ characterization is beneficial for samples such as optical fibers, which are difficult to handle in the standard analysis. Surface images taken by the OCT are compared with these common analysis tools such as scanning electron microscopy (SEM), reflected-light, and confocal microscopy. An axial resolution of approximately 126 nm for surface detection and a lateral resolution <2.5 microm are obtained and the potential of the setup to imaging structures with high aspect ratio is demonstrated.

  • [Show abstract] [Hide abstract]
    ABSTRACT: Although new affordable high-power laser technologies enable many processing applications in science and industry, depth control remains a serious technical challenge. In this Letter we show that inline coherent imaging (ICI), with line rates up to 312 kHz and microsecond-duration capture times, is capable of directly measuring laser penetration depth, in a process as violent as kW-class keyhole welding. We exploit ICI’s high speed, high dynamic range, and robustness to interference from other optical sources to achieve automatic, adaptive control of laser welding, as well as ablation, achieving 3D micron-scale sculpting in vastly different heterogeneous biological materials.
    Optics Letters 11/2014; 39(21). DOI:10.1364/OL.39.006217 · 3.39 Impact Factor
  • Planar Waveguides and other Confined Geometries, Edited by G. Marowsky, 01/2015: chapter Advanced coupling technologies to planar and strip waveguides: pages 169-183; Springer Series in Optical Sciences 189., ISBN: 978-1-4939-1178-3
  • [Show abstract] [Hide abstract]
    ABSTRACT: The future need for more bandwidth forces the development of optical transmission solutions for rack-to-rack, boardto- board and chip-to-chip interconnects. The goals are significant reduction of power consumption, highest density and potential for bandwidth scalability to overcome the limitations of the systems today with mostly copper based interconnects. For system integration the enabling of thin glass as a substrate material for electro-optical components with integrated micro-optics for efficient light coupling to integrated optical waveguides or fibers is becoming important. Our glass based packaging approach merges micro-system packaging and glass integrated optics. This kind of packaging consists of a thin glass substrate with integrated micro lenses providing a platform for photonic component assembly and optical fiber or waveguide interconnection. Thin glass is commercially available in panel and wafer size and characterizes excellent optical and high frequency properties. That makes it perfect for microsystem packaging. A suitable micro lens approach has to be comparable with different commercial glasses and withstand post-processing like soldering. A benefit of using laser ablated Fresnel lenses is the planar integration capability in the substrate for highest integration density. In the paper we introduce our glass based packaging concept and the Fresnel lens design for different scenarios like chip-to-fiber, chip-to-optical-printed-circuit-board coupling. Based on the design the Fresnel lenses were fabricated by using a 157 nm fluorine laser ablation system.
    Conference on Optical Interconnects XIV; 03/2014

Full-text (2 Sources)

Available from
Jun 1, 2014