• Kidd, M. D.
• Maier, Rrj
• Ardron, Marcus
• Albri, Frank
• Shephard, Jonathan D.
• Giet, Stephanie
• Hand, Duncan P.
• Weston, Nicholas J.

Abstract

<p>A Nd:YAG laser operating at 355 nm is used to emboss fine features on metals. The process relies on a combination of surface and bulk effects to texture and emboss surfaces to generate periodic features on the micron scale with sub-micron feature depth and has been termed YAGboss which is derived from embossing and the YAG laser used. The YAGboss process is predominantly controlled by surface tension effects, also known as Marangoni flows. The flows are a combination of pulsed laser-induced temperature gradients and temperature-dependent diffusion and chemical reactions occurring across an area heated by the incident laser radiation. In parallel to surface effects, bulk effects in close proximity to the surface also occur where changes in buoyancy induce convection flows and thermal currents. Both phenomena can be exploited to form surface textures by driving the local movements of the molten material before it re-solidifies some time after the end of the laser pulse. The process parameters vary strongly with minor changes in substrate composition. We present the application of the YAGboss process to the generation of sinusoidal surface diffraction gratings, and demonstrate the application of such a grating in an Optical Position Encoders (OPE).</p>

Topics

• impedance spectroscopy
• surface
• texture