Polaritonics: bridging the gap between electronics and photonics

Between electronics and photonics there exists a frequency gap of approximately 2 octaves, i.e. the frequency range between 100~GHz and 10~THz. Here we demonstrate that phonon-polaritons in ferroelectric crystals like LiNbO$_3$ or LiTaO$_3$ may be able to bridge this gap. The ability to fabricate structures within the crystal by femtosecond laser machining facilitates all integrated signal guiding and processing. Spatiotemporal imaging is employed for direct visualization of the electromagnetic field within the crystal. Polaritonic resonators, waveguides, photonic crystals and focusing, dispersive, and diffractive elements will be demonstrated.