Second harmonic generation in amorphous silicon-on-silica metamaterial

We demonstrate second harmonic generation by using an amorphous silicon metamaterial fabricated on the tip of an optical fiber that collects the generated light. The metamaterial is a double-chevron array that supports a closed-mode resonance for the fundamental wavelength at 1510 nm with a quality factor of 30. The normalized resonant second harmonic conversion efficiency calculated per intensity and square of interaction length is ∼10−11 W−1, which exceeds the previously achieved value for a silicon metamaterial by two orders of magnitude.