High-Q transverse-electric/transverse-magnetic photonic crystal nanobeam cavities

We experimentally demonstrate high quality factor dual-polarized photonic crystal nanobeam cavities. The free-standing nanobeams are fabricated in a 500 nm thick silicon layer, and are probed using both tapered optical fiber and free-space resonant scattering set-ups. We measure Q factors greater than 104 for both transverse magnetic (TM) and transverse electric modes, and observe fiber transmission drops as large as 1−T=0.8 at the TM mode resonances.