Terahertz supermirrors

Unprecedented ultrahigh-reflectance (R > 0.9995) in a one-dimensional photonic crystal (1D PC) mirror was experimentally demonstrated by using a terahertz time-domain spectroscopy (THz-TDS). The PC mirror was composed of three air gaps and four high-resistivity float zone (FZ) silicon layers, prepared by a high precision chemical mechanical polishing (CMP) machine. The power reflectance of 1D PC mirror is comparable to those of optical supermirrors (R > 0.9997).