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, ar...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.展开更多
The behavior of a negative refraction photonic crystal slab irradiated with out-of-plane incident beam is an unexplored subject.In such an experimental configuration,guided mode resonance appears in the reflection spe...The behavior of a negative refraction photonic crystal slab irradiated with out-of-plane incident beam is an unexplored subject.In such an experimental configuration,guided mode resonance appears in the reflection spectrum.We show that,in this case,the light coupled inside the photonic crystal is backpropagating.A relationship with the negative index properties is established using a new approach in which the guided resonance is recovered by modeling the photonic crystal layer with a simple Lorentz resonator using the Fresnel reflection formula.展开更多
In this work,we present the first experimental evidence of negative dielectric susceptibility in a two-dimensional silicon photonic crystal(PhC)with negative refractive index behavior.In the frequency range in which t...In this work,we present the first experimental evidence of negative dielectric susceptibility in a two-dimensional silicon photonic crystal(PhC)with negative refractive index behavior.In the frequency range in which the effective refractive index neff is equal to 21,the incident light couples efficiently to the guided modes in the top surface layer of the PhC metamaterial.These modes resemble surface plasmon polariton resonances.This finding was confirmed by ellipsometric measurements,demonstrating the isotropy of the PhC resonances.Such negative index PhC materials may be of use in biosensing applications.展开更多
文摘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.
基金Portions of this work were performed at the Molecular Foundry,Lawrence Berkeley National Laboratory,which is supported by the Office of Science,Office of Basic Energy Sciences,of the US Department of Energy under contract no.DE-AC02-05CH11231This work was partially supported by the Italian Ministry of University and Research under grants PON PANDION 01_00375.
文摘The behavior of a negative refraction photonic crystal slab irradiated with out-of-plane incident beam is an unexplored subject.In such an experimental configuration,guided mode resonance appears in the reflection spectrum.We show that,in this case,the light coupled inside the photonic crystal is backpropagating.A relationship with the negative index properties is established using a new approach in which the guided resonance is recovered by modeling the photonic crystal layer with a simple Lorentz resonator using the Fresnel reflection formula.
基金Portions of this work were completed as part of a user project at the Molecular Foundry,Lawrence Berkeley National Laboratory,which is supported by the US Department of Energy under contract DE-AC02-05CH11231We gratefully acknowledge Aleksandr Polyakov for his suggestions in critically revising the manuscript.This work was partially supported by Italian National Operative Programs PON01_02782,PON01_01525 and PON01_00375.
文摘In this work,we present the first experimental evidence of negative dielectric susceptibility in a two-dimensional silicon photonic crystal(PhC)with negative refractive index behavior.In the frequency range in which the effective refractive index neff is equal to 21,the incident light couples efficiently to the guided modes in the top surface layer of the PhC metamaterial.These modes resemble surface plasmon polariton resonances.This finding was confirmed by ellipsometric measurements,demonstrating the isotropy of the PhC resonances.Such negative index PhC materials may be of use in biosensing applications.
