Photonic crystals built by time in ancient Roman glass.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 37722057.
- Also identified by DOI 10.1073/pnas.2311583120 and PMC identifier 10523479.
- Licence recorded as CC BY-NC-ND.
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Abstract
Ancient glass objects typically show distinctive effects of deterioration as a result of environmentally induced physicochemical transformations of their surface over time. Iridescence is one of the distinctive signatures of aging that is most commonly found on excavated glass. In this work, we present an ancient glass fragment that exhibits structural color through surface weathering resulting in iridescent patinas caused by silica reprecipitation in nanoscale lamellae. This archaeological artifact reveals an unusual hierarchically assembled photonic crystal with extremely ordered nanoscale domains, high spectral selectivity, and reflectivity (~90%), that collectively behaves like a gold mirror. Optical characterization paired with nanoscale elemental analysis further underscores the high quality of this structure providing a window into this sophisticated natural photonic crystal assembled by time.