What is the ideal refractive index difference for achieving invisibility?

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SUMMARY

The ideal refractive index difference for achieving invisibility is determined by the proximity of two refractive indices. In this discussion, a glass fiber with a refractive index of 1.521 is compared to two resin systems, one at 1.506 and another at 1.4736. The resin with a refractive index of 1.506 is identified as the better match, but the effectiveness of invisibility also depends on measurement sensitivity. Tools such as an Abbe refractometer and differential interference microscopy are essential for evaluating index matching and its impact on visibility.

PREREQUISITES
  • Understanding of refractive index and its significance in optics
  • Familiarity with Abbe refractometers for precise measurement
  • Knowledge of differential interference microscopy techniques
  • Basic principles of Fresnel equations for calculating reflection coefficients
NEXT STEPS
  • Research the properties and applications of Cargille and Norland resin systems
  • Explore advanced techniques in differential interference microscopy
  • Study the Fresnel equations in detail to understand reflection coefficients
  • Investigate general rules of thumb for refractive index matching across various materials
USEFUL FOR

Optical engineers, materials scientists, and researchers focused on optical invisibility and index matching in composite materials.

lanik05
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I was wondering how close 2 refractive Indexes have to be in order to be not visible? I currently have a glass fiber at 1.521 and am researching resin systems to match and so far have 2 - one at 1.506 and the other at 1.4736. I know which one is better (1.506), but is it close enough to "disapear"?
 
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It depends on how sensitive your measurement is. I've used an Abbe refractometer that measured the refractive index down to 0.1% error, and using index-matching fluids I've used differential interference microscopy to observe particles with an index mismatch slightly above that.

Have you talked with Cargille? Another company worth talking to is Norland. Either can help you with your specific application needs better than I.
 
You can calculate reflection coefficient using Fresnel equations: http://en.wikipedia.org/wiki/Fresnel_equations"

see also: http://reflectioncoefficient.info/"
 
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Thanks for the inquiries. Is there just a general rule of thumb for how far apart the RI's can be for the majority of materials or is there always other factors that can play a significant role in how well a material will "disapear" into another?
 

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