Ultrahigh-Q TE/TM dual-polarized photonic crystal holey fishbone-like nanobeam cavities

We propose and theoretically investigate a one-dimensional photonic crystal holey fishbone-like silicon nanobeam cavity that simultaneously supports both fundamental transverse-electric (TE) and second-order transverse-magnetic (TM) modes, and modes. Three-dimensional finite-difference time-domain simulations show that with thin cavity thickness and compact cavity size, the cavity possesses ultrahigh Q ( , ), along with small mode volume and high confinement factor, for both and modes. We believe our proposed cavity could be beneficial for nonlinear frequency conversion, optomechanics and other applications where dual-polarized TE/TM modes are needed.