L3 Photonic Crystal Nanocavities with Measured Q-factor Exceeding One Million

We experimentally demonstrate ultra-high quality factors (Q= 1.45×106) in evolutionary optimized 2D L3 photonic crystal nanocavities fabricated in Si slabs. Together with ultra-small effective mode volumes ~ 0.96(λ/n)3, such a nanocavity offers a new platform in future integrated nanophotonics.