Fabrication of dye-infiltrated macroporous silica for laser amplification

Abstract

We have fabricated a dielectrically disordered medium based on monolithic silica (SiO2) with interconnected macropores by a sol–gel method. Macroporous SiO2 is obtained in a system containing tetramethoxysilane, poly(ethylene glycol), acetic acid, and water. The macroporous structure is formed when the transient structure of phase separation developed during the hydrolysis and polycondensation of alkoxysilane is frozen by the sol–gel transition. An active disordered medium is prepared by infiltrating a methanol solution of rhodamine 6G (R6G) dye into the macropores of the monolithic SiO2. When R6G dye molecules filled in the interconnected macropores are pumped by a frequency-doubled Nd:YAG laser, a drastic narrowing of dye emission accompanied by an increase in the peak intensity is observed. The large optical gain is ascribed to the increase in residence time of emitted photons in the active region due to multiple scattering.