Spectroscopy study of Yungang Grottoes weathered material in terahertz range

A spectroscopy study using terahertz time domain spectroscopy (THz-TDS) reveals distinct spectral characteristics of weathered material samples from the Yungang Grottoes. The research identifies that transmission coefficients are high at low frequencies but decrease at higher frequencies across all three sampled caves, dated A.D. 484, A.D. 494, and A.D. 520. Notably, the absorption coefficient increases exponentially with frequency, a trend more pronounced in samples from later periods. The study also highlights significant differences in refractive indices (1.53, 1.57, and 1.51) among the caves, enabling differentiation based on their weathering patterns. These findings provide critical optical constants for Yungang Grottoes materials, offering valuable insights for further studies.

Meng, T.-h., Yang, C.-q., Lu, Y.-h., & Zhao, G.-z. (2011). Spectroscopy study of Yungang Grottoes weathered material in terahertz range. International Symposium on Photoelectronic Detection and Imaging 2011: Terahertz Wave Technologies and Applications, 8195, 81951C. https://doi.org/10.1117/12.900825