Formation of photonic structures in Sm2+-doped aluminosilicate glasses through phase separation

Sm²⁺-doped Al₂O₃–SiO₂ glasses with three-dimensionally interconnected macroporous morphology have been prepared via the alkoxide-derived sol–gel process containing poly(ethylene oxide) and SmCl₃ · 6H₂O. The macroporous morphology is obtained by concurrently inducing the phase separation and sol–gel transition. When the macroporous aluminosilicate glasses doped with Sm²⁺ are irradiated with a visible light laser at the wavelength of 488 nm, a hole or a dip appears in the plot of fluorescence intensity versus the incident angle of laser beam, indicating that the valence state of Sm²⁺ is spatially modulated through the interference of multiply scattered light. The hole profile can be controlled by adjusting the macroporous morphology.