Simultaneous broadening and enhancement of the 1.5 μm photoluminescence peak of Er3+ ions embedded in a 1-D photonic crystal microcavity

It is proposed for the first time that the 1.5 mu m Er3+ photoluminescence peak may be significantly broadened by a photonic crystal microcavity structure. Two coupled microcavities have been designed and prepared by sol-gel processing based on alternating layers of silicate glass and titania materials. The 1.5 mu m emission spectra of the Er3+ ions embedded in these microcavity structures are measured and discussed. It is found that the spontaneous emission spectra are effectively broadened to a point where they become approximately square in shape. The full width at half maximum (FWHM) reached a value as large as 183 nm, which is the best result reported so far. The measured photoluminescence profiles agree well with simulated curves and an intensity enhancement by the microcavities has also been observed. These results may be of significance for applications requiring broadened or otherwise modified spontaneous emission spectra, such as application-specific LEDs and other non-coherent light sources. The present technique can easily be applied to other active materials.