Typical data obtained. (a) Measured reflectance, D1, (2 mg SR101) as a function of the radiation energy and the angle of incidence. Inset shows the reflectance as a function of energy at the 63° excitation angle (red dashed line). (b) Normalized intensity of D2 signal from the same sample. Due to the weakness of the high energy peaks at D2, we zoom on the high energy region (indicated as green rectangle). Corresponding scale bar is presented within green rectangle. Inset shows the intensity as a function of the energy at the 63° excitation angle (red dashed line).