Liquid Crystal Active Metasurface for Ultra-Selective Wavelength Switching

In this work, a novel wavelength selective switch is proposed and demonstrated. This new configuration avoid the use of grating and lenses, as a result, a very compact and lightweight ultra-selective wavelength switch can be obtained. For this, a novel tunable ultra-selective mirror is used. The tunability is achieved by using LC, the ultra-high Q-factor is obtained by means of dielectric metasurfaces based on hollow core nanocuboids. The metasurfaces are placed in the optical path with a specific angle. Each mirror can select any specific wavelength by applying an AC voltage. For 10°, a 44 nm of tunable range is possible. Absorption is negligible for low applied voltages. The bandwidth of the reflection resonance at 10° , ranges from 0.02 nm to 0.035 nm, corresponding to a 2.5 GHz and 4.5 GHz resolution, respectively. This is far beyond the required bandwidth for future Ultra-DWDM systems.