Measurements of optical electric field intensities in microcavities using thin emissive polymer films

The behavior of chromophores in microcavities-Fabry-Perot resonators with thickness of the order of the wavelength of light that are introduced into Light-emitting devices to improve performance-is reported. Strong modification of the absorption and the spontaneous emission rates of the chromophores is demonstrated for thin luminescent layers of polyphenylene derivatives placed at different positions in the cavities. The technique of measurement is detailed and the implications of the results are discussed.