THz反射镜 太赫兹反射镜 THz Mirrors 太赫兹光谱反射 太赫兹系统搭建 THz Mirrors Material Quartz Glass Type Plano-Plano Dimensions Tolerance ±0.25mm Clear Aperture ≥90% Surface Quality of Polished Surfaces 40/20 Scr/Dig Surface Quality of Ground Surface 2.5 Ra Surface Accuracy 1/2 λ at 633nm Coating Protected Gold Thickness of Gold Layer 400nm