Organic multilayers as distributed Bragg reflectors

We report on a distributed Bragg reflector ~DBR! operating in the IR spectral region, based on a fluorocarbon polymer (CFx) multilayer. In this organic structure, the periodic variation of the refractive index is obtained by embedding gold clusters in the CFx , resulting in a periodic CFx /CFx(Au) layered structure with a refractive index discontinuity in the infrared spectral region of about Dn;0.4. We have fabricated a quarter-wavelength stack consisting of 4 CFx /CFx(Au) pairs, with a nominal Au concentration equal to 17%. The DBR shows a reflectance peak of about 70% at 1.7 mm and a full width at half maximum of about 0.4 m