High-speed free-space modulators using nanometallic and metasurface resonators

Surface-normal electro-optic modulators are promising for a wide range of emerging applications, including high-speed beam shaping, free-space optical communication, high-density optical interconnects, and photonic neuromorphic computing. We have been developing various types of active nanometallic and metasurface devices with organic electro-optic (OEO) materials, operating in the near-infrared wavelength. By trapping the normally incident light to high-Q quasi-bound state in the continuum (qBIC) modes, which are tightly confined inside the subwavelength grating structures, we have successfully demonstrated highly efficient modulation using ultrathin devices with 3-dB bandwidth exceeding gigahertz.