Surface-Enhanced Raman and Fluorescence Spectroscopy with an All-Dielectric Metasurface

Romano, Silvia; Zito, Gianluigi; Calafiore, Giuseppe Carlo; Penzo, Erika; Cabrini, Stefano; Mocella, Vito

doi:10.1021/acs.jpcc.8b03190

Cited by 86 publications

(71 citation statements)

References 44 publications

(92 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These special modes possess an ideal infinite Q-factor characterized by vanishing resonance linewidth since can be completely decoupled from the continuum of propagating free-space radiation [20][21][22]. Surprisingly, experimental deviation from an ideal behavior due to unavoidable radiation loss channels (like scattering from imperfections and material absoprtion) permits a partial coupling to external radiation and actually makes BIC resonators among the most effective light-matter interaction platforms [23][24][25][26]. There are mainly two mechanisms of ideal decoupling from the continuum.…”

Section: Introductionmentioning

confidence: 99%

Tuning the exponential sensitivity of a bound-state-in-continuum optical sensor

Romano¹,

Zito²,

Yépez³

et al. 2019

Opt. Express

Self Cite

View full text Add to dashboard Cite

In this work, we investigate the evanescent field sensing mechanism provided by an all-dielectric metasurface supporting bound states in the continuum (BICs). The metasurface is based on a transparent photonic crystal with subwavelength thickness. The BIC electromagnetic field is localized along the direction normal to the photonic crystal nanoscale-thin slab (PhCS) because of a topology-induced confinement, exponentially decaying in the material to detect. On the other hand, it is totally delocalized in the PhCS plane, which favors versatile and multiplexing sensing schemes. Liquids with different refractive indices, ranging from 1.33 to 1.45, are infiltrated in a microfluidic chamber bonded to the sensing dielectric metasurface. We observe an experimental exponential sensitivity leading to differential values as large as 226 nm/RIU with excellent FOM. This behavior is explained in terms of the physical superposition of the field with the material under investigation and supported by a thorough numerical analysis. The mechanism is then translated to the case of molecular adsorption where a suitable theoretical engineering of the optical structure points out potential sensitivities as large as 4000 nm/RIU.

show abstract

Section: Introductionmentioning

confidence: 99%

Tuning the exponential sensitivity of a bound-state-in-continuum optical sensor

Romano¹,

Zito²,

Yépez³

et al. 2019

Opt. Express

Self Cite

View full text Add to dashboard Cite

show abstract

“…Indeed, radiated fields with momentum close to the BIC point have a polarization winding in a vortex structure around the BIC core, as also recently experimentally verified [13,14]. A striking feature is that the electromagnetic field of a BIC is characterized by a diverging lifetime, or an infinite radiative Q-factor [3,12], from which light-matter interaction could be highly enhanced [16][17][18][19]. Reciprocity implies that far-field excitation of an ideal (infinite Q-factor) BIC mode is not possible.…”

Section: Introductionmentioning

confidence: 75%

“…1(a)-1(b)] (Supplement 1, Section 1). This material is transparent in both visible and infrared ranges of light and has a real-part refractive index of 2.15 at 532 nm [17]. The unit cell design does not break in-plane inversion symmetry (C 2 symmetry), as visible in Fig.…”

Section: Numerical Modeling and Rationale Of The Phenomenonmentioning

confidence: 99%

“…Reciprocity implies that far-field excitation of an ideal (infinite Q-factor) BIC mode is not possible. However, real structures can have finite, arbitrarily large Q-factors close enough to the BIC point, and partial coupling to the input light makes its spectral signature to appear as a special Fano-shaped resonance in quasi-BIC regime, which can be exploited for several applications [17][18][19][20]. In addition, of a certain interest is also the polarization structure of the quasi-BIC radiation [21,22].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Observation of spin-polarized directive coupling of light at bound states in the continuum

Zito

Romano

Cabrini

et al. 2019

Optica

Self Cite

View full text Add to dashboard Cite

Spin-polarized directive coupling of light associated with the photonic quantum spin-Hall effect (QSHE) is a nanoscale phenomenon based on strong spin-orbit interaction that has recently attracted significant attention. Herein, we discuss the experimental manifestation of QSHE intrinsic in the Bloch waves associated with a bound state in the continuum (BIC) of a dielectric photonic crystal metasurface (PhCM). We show numerically that BICs in nanoscale PhCMs have photonic spin angular momentum density transverse to the orbital momentum not only at the interfaces but also inside the confining dielectric medium. Then, we experimentally demonstrate that the fundamental Bloch waves of the BIC mode, macroscopically amplified on resonance, propagate along the symmetry axes of the PhCM obeying spin-momentum locking also at normal incidence, i.e., with no symmetry breaking. This BIC-enhanced spindirective coupling of light may enable versatile implementations of spin-optical structures, paving the way for novel photonic spin multiplatform devices.

show abstract

“…Recent achievements in the field of BIC are discussed in Refs. [17][18][19][20][21][22][23][24][25][26].…”

Section: Introductionmentioning

confidence: 99%

Multipolar origin of bound states in the continuum

et al. 2019

View full text Add to dashboard Cite

Metasurfaces based on resonant subwavelength photonic structures enable novel ways of wavefront control and light focusing, underpinning a new generation of flat-optics devices. Recently emerged all-dielectric metasurfaces exhibit high-quality resonances underpinned by the physics of bound states in the continuum that drives many interesting concepts in photonics. Here we suggest a novel approach to explain the physics of bound photonic states embedded into the radiation continuum. We study dielectric metasurfaces composed of planar periodic arrays of Mie-resonant nanoparticles ("meta-atoms") which support both symmetry protected and accidental bound states in the continuum, and employ the multipole decomposition approach to reveal the physical mechanism of the formation of such nonradiating states in terms of multipolar modes generated by isolated meta-atoms. Based on the symmetry of the vector spherical harmonics, we identify the conditions for the existence of bound states in the continuum originating from the symmetries of both the lattice and the unit cell. Using this formalism we predict that metasurfaces with strongly suppressed spatial dispersion can support the bound states in the continuum with the wavevectors forming a line in the reciprocal space. Our results provide a new way for designing high-quality resonant photonic systems based on the physics of bound states in the continuum.

show abstract

Surface-Enhanced Raman and Fluorescence Spectroscopy with an All-Dielectric Metasurface

Cited by 86 publications

References 44 publications

Tuning the exponential sensitivity of a bound-state-in-continuum optical sensor

Tuning the exponential sensitivity of a bound-state-in-continuum optical sensor

Observation of spin-polarized directive coupling of light at bound states in the continuum

Multipolar origin of bound states in the continuum

Contact Info

Product

Resources

About