Image Contrast Immersion Method for Measuring Refractive Index Applied to Spider Silks

Abstract

A technique for measuring the refractive index of micron sized fibers using a series of immersion index matching oils, and image contrast measurements is proposed and demonstrated. It has been applied to radial silks of the orb web weaving spider Plebs eburnus. These have widths of ~1-2 microns. Values about 1.5500 are obtained, with birefringence values between 0.0000 and 0.0133 for individual silks. An uncertainty in the range +/- 5 x 10(exp -4) to +/- 2 x 10(exp -3) is achieved for these challenging samples. This accuracy is about a twenty times improvement on previously reported measurements for spider silks using other techniques. The technique is used to obtain measurements of the refractive index of spider silks as a function of wavelength, for the first time. An Abbe number for the radial silks of Plebs eburnus of ~32 is found.

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Document Details

Document Type
Technical Report
Publication Date
Sep 26, 2011
Accession Number
ADA557832

Entities

People

  • D. M. Kane
  • Douglas J Little

Organizations

  • Macquarie University

Tags

Communities of Interest

  • Advanced Electronics
  • Air Platforms

DTIC Thesaurus Topics

  • Accuracy
  • Fibers
  • Focal Planes
  • Materials
  • Measurement
  • Mechanical Properties
  • Optical Fibers
  • Optical Materials
  • Optical Properties
  • Optics
  • Refractive Index
  • Spiders

Fields of Study

  • Physics

Readers

  • Energy Conservation and Renewable Energy Engineering.
  • Optical Physics and Photonics.