Secondary radiation of synthetic opals loaded by the sodium nitrite ferroelectric

This paper reports on a comparison of transmission, reflection, and secondary radiation spectra of unloaded synthetic opals and samples filled with the sodium nitrite ferroelectric (NaNO₂). The radiation is provided by semiconductor light-emitting diodes operating in the ultraviolet and visible spectral regions. Selective excitation of slow electromagnetic waves in a photonic crystal, an effect observed when the exciting radiation frequency approaches the stop-band edge, is studied.