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Updated: Jul 16, 2025
11:08
Fabrication And Characterization Of Photonic Crystal Slow Light Waveguides And Cavities
Published on: November 30, 2012
19.0K
Photonic crystals built by time in ancient Roman glass
Giulia Guidetti1, Roberta Zanini2, Giulia Franceschin2
1Silklab, Department of Biomedical Engineering, Tufts University, Medford, MA 02155.
Summary
Ancient glass fragments can develop iridescent patinas due to natural weathering. This study reveals such a fragment acts as a sophisticated, naturally assembled photonic crystal, mimicking a gold mirror.
Area of Science:
- Archaeological science
- Materials science
- Optics
Background:
- Ancient glass objects exhibit surface deterioration from environmental factors.
- Iridescence is a common aging signature on excavated glass, resulting from surface transformations.
Purpose of the Study:
- To investigate the structural basis of iridescence in an ancient glass fragment.
- To characterize the photonic properties of the weathered glass surface.
Main Methods:
- Optical characterization techniques.
- Nanoscale elemental analysis.
Main Results:
- The ancient glass fragment displays structural color due to silica reprecipitation in nanoscale lamellae.
- The weathered surface forms a hierarchically assembled photonic crystal with highly ordered nanoscale domains.
- The structure exhibits high spectral selectivity and reflectivity (~90%), functioning like a gold mirror.
Conclusions:
- The iridescent patina on the ancient glass is a high-quality, naturally assembled photonic crystal.
- This finding offers insights into sophisticated natural photonic structures formed over time.
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