Toward an ideal nanomaterial for on-chip Raman laser

One of the most important applications of stimulated Raman scattering (SRS) is the realization of ampli¯ers or laser sources in bulk materials, in ¯ber and in integrated optic format as well. We note that, as a general rule, in all laser gain bulk materials, there is a tradeo® between gain and bandwidth: line width may be increased at the expense of peak gain. This tradeo® is a fundamental limitation toward the realization of micro/nano-sources with large emission spectra. In this paper, in order to clarify the possibility of obtaining new materials with both large Raman gain coe±cients and spectral bandwidth, SRS investigations in nanostructures, spanning from nanometrically heterogeneous K2O–Nb2O5SiO2 (KNS) glasses to Si nanocrystals, are reported and discussed.