Ultralow-loss CMOS copper plasmonic platform

The size of photonic components is fundamentally limited by the diffraction of light, while miniaturization is one of the key concepts in the development of high-speed and energy-efficient electronic and optoelectronic chips. Plasmonics attracts great interest thanks to the unique opportunity to confine light to a space much smaller than the light wavelength by converting it into surface plasmons. However, this ability to get over the diffraction limit comes at a cost of strong signal attenuation due to absorption in the metal, and characteristics acceptable for practical applications have been demonstrated only with noble metals - gold and silver. These materials do not enter into chemical reactions and therefore they are not compatible with industry-standard fabrication processes, such as CMOS technology. Recent research efforts have brought novel materials, such as titanium nitride, to plasmonics [1]. Despite that they are perspective for different metamaterial applications, these materials cannot compete with silver and gold in infrared plasmonics [2,3].