Photonics Research, 2018, 6 (7): 07000726, Published Online: Jul. 4, 2018
Label-free sensing of ultralow-weight molecules with all-dielectric metasurfaces supporting bound states in the continuum Download: 638次
Abstract
The realization of an efficient optical sensor based on a photonic crystal metasurface supporting bound states in the continuum is reported. Liquids with different refractive indices, ranging from 1.4000 to 1.4480, are infiltrated in a microfluidic chamber bonded to the sensing dielectric metasurface. A bulk liquid sensitivity of 178 nm/RIU is achieved, while a Q -factor of about 2000 gives a sensor figure of merit up to 445 in air at both visible and infrared excitations. Furthermore, the detection of ultralow-molecular-weight (186 Da) molecules is demonstrated with a record resonance shift of 6 nm per less than a 1 nm thick single molecular layer. The system exploits a normal-to-the-surface optical launching scheme, with excellent interrogation stability and demonstrates alignment-free performances, overcoming the limits of standard photonic crystals and plasmonic resonant configurations.
Silvia Romano, Gianluigi Zito, Stefania Torino, Giuseppe Calafiore, Erika Penzo, Giuseppe Coppola, Stefano Cabrini, Ivo Rendina, Vito Mocella. Label-free sensing of ultralow-weight molecules with all-dielectric metasurfaces supporting bound states in the continuum[J]. Photonics Research, 2018, 6(7): 07000726.