# Terahertz Frequency-Modulated Continuous-Wave Inspection of an Ancient Enamel Plate

## TL;DR

Terahertz imaging is shown to effectively inspect historical enamel plates without damaging them, revealing hidden features and textures.

## Contribution

The study demonstrates the practicality of terahertz FMCW imaging for non-destructive cultural heritage analysis.

## Key findings

- Terahertz imaging revealed subsurface fractures and surface textural variations in an enamel plate.
- Contrast variations in THz images suggest correlations with material composition.
- The technique is presented as a compact and non-contact diagnostic tool suitable for in situ inspections.

## Abstract

This study investigates the application of terahertz frequency-modulated continuous-wave (FMCW) imaging for the non-destructive inspection of a historical enamel plate, using both reflection and transmission modes. A 300 GHz FMCW radar system was employed to capture high-resolution images of the plate’s internal and surface structures. Through optimized data acquisition and processing, the system successfully revealed subsurface features such as fractures, as well as surface-level textural variations linked to the decorative glazes. Although pigment differentiation remains a challenge, contrast variations observed in THz images suggest correlations with material composition. The results highlight the potential of FMCW terahertz imaging as a compact, rapid, and non-contact diagnostic tool for cultural heritage analysis. Its practicality and adaptability make it particularly suitable for in situ inspections in museums or restoration contexts.