Fast electroholographic wavelength selective switching implemented in a slab waveguide.

We present wavelength selective switching with a rise time of 25 ns implemented in a slab waveguide constructed in a KLTN:Cu crystal. The waveguide was fabricated by implantations of alpha particles at 2.1 MeV which produced a 0.5 µm thick cladding layer with reduced refractive index at 4.5 µm underneath the crystal surface. This demonstrates the feasibility of implementing electroholography in waveguides maintaining the performance obtained in bulk crystals, providing in potential the basis for constructing integrated photonic circuits which incorporate interconnected electroholographic wavelength selective switches and electrical wavelength tuning devices for employing wavelength addressing routing schemes in computer networks, in particular for relieving the bandwidth bottlenecks in data center networks.

Hyperbolic optics and superlensing in room-temperature KTN from self-induced k-space topological transitions.

A hyperbolic medium will transfer super-resolved optical waveforms with no distortion, support negative refraction, superlensing, and harbor nontrivial topological photonic phases. Evidence of hyperbolic effects is found in periodic and resonant systems for weakly diffracting beams, in metasurfaces, and even naturally in layered systems. At present, an actual hyperbolic propagation requires the use of metamaterials, a solution that is accompanied by constraints on wavelength, geometry, and considerable losses. We show how nonlinearity can transform a bulk KTN perovskite into a broadband 3D hyperbolic substance for visible light, manifesting negative refraction and superlensing at room-temperature. The phenomenon is a consequence of giant electro-optic response to the electric field generated by the thermal diffusion of photogenerated charges. Results open new scenarios in the exploration of enhanced light-matter interaction and in the design of broadband photonic devices.