Silicon nano-membrane based photonic crystal microcavities for high sensitivity bio-sensing

We experimentally demonstrated photonic crystal microcavity based resonant sensors coupled to photonic crystal waveguides in silicon nano-membrane on insulator for chemical and bio-sensing. Linear L-type microcavities are considered. In contrast to cavities with small mode volumes, but low quality factors for bio-sensing, we showed increasing the length of the microcavity enhances the quality factor of the resonance by an order of magnitude and increases the resonance wavelength shift while retaining compact device characteristics. Q similar to 26760 and sensitivity down to 15 ng/ml and similar to 110 pg/mm(2) in bio-sensing was experimentally demonstrated on silicon-on-insulator devices. (C) 2012 Optical Society of America