A team of researchers from Cambridge University in the UK has built a microcavity that could be suitable as an efficient and tunable wavelength converter. The cavity enhances the rate of emission at the resonance wavelengths of the cavity while suppressing other wavelengths. The device comprises a thin film of a fluorescent semiconducting polymer combined with an electrically switchable liquid crystal layer. The polymer and the crystal layer are sandwiched between the two cavity mirrors. The group achieved shifts of 56 nm in wavelength. Unlike filters, microcavities achieve wavelength emission tuning by channeling radiation power at resonant modes. The device absorbed light at short wavelengths in the blue and UV range. It then emitted light in part of the spectrum where there is no control of the emission wavelength.