Anodically oxidized porous alumina whose structure can be described as a closepacked array of columnar cells

each containing fine

regular

almost cylindrical

parallel-sided pores

can be utilized as transparent host template for a variety of luminescent media.RhB laser dyes were successfully embedded in the porous alumina.We studied the photoluminescence of the compound films and compared it with the PL of the liquid dyes.It was found that the PL of the embedded dyes is like the PL of the liquid dyes at low concentration

but the spectra symmetry of the embedded dyes is better than that of the liquid dyes.The experimental results suggest that the laser dyes mainly exist in porous alumina in form of the monomer. To clarify the detailed state of the dyes existing in the porous alumina

we have done a series of experiments.(1)Porous alumina were formed at various anodizing time in the range 30 to 90min at constant voltage 15V in 15% sulfuric acid at 25℃.The intensity of the PL of the embedded dyes increases and the peak exhibits red shift as the anodizing time grows.(2)Porous alumina were formed at various constant voltages in the range 5V to 17V for 1h in 15% sulfuric acid at 25℃.The intensity of the PL of the embedded dyes increases and the peak exhibits red shift as the anodizing voltage increases.(3)Porous alumina were formed at 15V for 1h in sulfuric acid at 25℃

and immersed in the dyes at various concentration in the solution.RhB output from the embedded layer is as a function of dye concentration in the solution.The peak of the luminescence exhibits red shift

but severe concentration quenching is apparent for impregnation from solutions stronger than 10

-2

M/L. Finally

we put forward an idealized model to explain the state of RhB laser dyes embedded in porous alumina.The dye is roughly absorbed on the wall of the pore and mainly exists in the form of monomer.