Enhanced four-wave mixing from multi-resonant silicon dimer-hole membrane metasurfaces

Abstract

Tailoring optically resonant features in dielectric metasurfaces unveils a robust scheme to control electromagnetic near fields of light and thus to boost the nanoscale nonlinear light-matter interactions. Membrane metasurfaces offer unique possibilities for supporting multipolar resonances and meanwhile maintaining high mode volume for enhancing nonlinear frequency conversion. Here we design a silicon membrane metasurface consisting of dimer airy holes, as a versatile platform for generating four-wave mixing (FWM). We show that such a metasurface exhibits a multi-resonant feature, including a quasi bound state in the continuum (BIC) generated by the collective toroidal dipole mode excited in the designed subdiffractive periodic system. We show that via employing the BIC mode in the short-wave infrared (SWIR), together with other resonant enhanced electric near fields in near-infrared (NIR) region, simultaneously, one can convert invisible SWIR light to visible light radiation with high efficiency, via FWM. We experimentally demonstrated a significant four-wave mixing emission enhancement from our metasurface, which leads to a conversion efficiency of 1.2×10-6 using pump and signal beam peak intensities as low as 0.24 GW/cm-2 and 0.14 GW/cm-2, respectively. Our results open new routes for enhancing nonlinear efficiencies for up-conversion processes.

Polarization-controlled dynamically switchable high-harmonic generation from all-dielectric metasurfaces governed by dual bound states in the continuum

“…Its radiation channel can be closed by changing the spacing distance d of the nanodimers, rendering infinitely small resonance width at d = 60 nm, which is a typical parameter tuning behavior of the so-called accidental BIC. In contrast to the symmetry-protected BIC, there is no symmetry perturbation in the parameter tuning of the accidental BIC 18,51,54,59 . In Fig.…”

“…The wavelength-dependent complex refractive index of Si is extracted from experimental data 49 , and the constant refractive index of 1.45 is assigned to SiO 2 . Note that we choose the dimer design as it belongs to a symmetric geometry of C 2v group and possesses more structural parameters to be tuned than C 4v configurations [50][51][52][53][54][55][56][57][58][59] . Benefiting from the additional degree of freedom, it is possible to manipulate the excitation of dual BIC resonances by adjusting the structural geometry and rotating the fundamental pump polarization.…”

Recent advances in strongly resonant and gradient all-dielectric metasurfaces

“…Finally, a dual-band, qBIC Si metasurface was theoretically proposed for polarization-sensitive, efficient third-and fifth-harmonic generation, the latter by a direct or cascaded, through degenerate four-wave mixing (DFWM), process 75 . Efficient DFWM has also been recently demonstrated in a qBIC Si dimer-hole membrane metasurface with pump and signal wavelength (peak intensity) at 840 nm (I p = 0.33 GW/cm −2 ) and 1565 nm (I s = 0.17 GW/cm −2 ), respectively 76 . The metasurface supported two qBIC resonances at the pump and signal wavelengths, yielding a conversion efficiency η FWM = P FWM /P s = 0.76 × 10 −6 .…”

Localized Nanopore Fabrication via Controlled Breakdown

“…Optical nanopores [ 96 ] can benefit from the high bandwidth of optical measurements, as well as the ease of monitoring optical signals at high throughput [ 22 , 96 , 97 , 98 , 99 , 100 , 101 , 102 , 103 , 104 , 105 , 106 , 107 , 108 , 146 , 147 , 148 ]. On the other hand, nanopore techniques can actively deliver target molecules into the optical sensing area instead of relying on diffusion or tethering [ 95 , 105 , 110 , 112 , 149 ].…”

“…In recent years, combining nanopore sensing with fluorescence and plasmonic optical measurements has drawn more and more interest, because optical signals provide additional depth of information without interfering with the electrical signal [ 22 , 96 , 97 , 98 , 99 , 100 , 101 , 102 , 103 , 104 , 105 , 106 , 107 , 108 ]. In addition, the research field of plasmonic optical sensing, or fluorescence-based single-molecule sensing, could benefit from the electrical signal of nanopore sensing.…”