Analysis and Optimization of Light Absorption and Scattering Properties of Metal Nanocages.

Metal nanocages exhibit localized surface plasmon resonance that strongly absorbs and scatters light at specific wavelengths, making them potentially valuable for photothermal therapy and biological imaging applications. However, investigations on metal nanocages are still confined to high-cost and small-scale synthesis. The comprehensive analysis of optical properties and optimal size parameters of metal nanocages is rarely reported.

Multiplexed rectangular dielectric gratings with multiple narrow-band refractive index filtering and sensing.

We propose a low-loss compound structure consisting of a multiplexed rectangular dielectric grating and a waveguide layer, which can function as multi-band optical filters and sensors in TE and TM polarization by utilizing the resonant mode of the waveguide (WG) and the hybrid SP, respectively. By manipulating the parameters and subsequently constraining the local density of multi-resonant modes to several distinct resonant wavelengths, we propose a novel category of highly sensitive refractive index sensing platforms. Spectral shifts ranging from 110 to 131 nm/RIU with FOM of (22, 26.

Narrower-band multiplet resonances of surface plasmons on periodically phase-shifted metal gratings.

In this Letter, we report properties of surface plasmon resonances (SPRs) on metal gratings with periodic phase shifts, in which high-order SPR modes corresponding to the long-pitch (a few to tens of wavelengths, λ) phase shifts are excited, instead of those corresponding to the short-pitch (∼λ) gratings. In particular, it is shown that, for quarter-phase shifts, spectral features of doublet SPR modes with narrower bandwidths are notably present when the underlying first-order short-pitch SPR mode is designed to be located between an arbitrarily chosen pair of neighboring high-order long-pitch SPR modes. Also, the positions and interspacing of the doublet SPR modes can be arbitrarily tuned by adjusting the pitch values.

Multiplet independent resonance modes in multiplexed gratings.

Resonance modes in usual optical resonators are orthogonal, but correlated and their resonance properties cannot be independently controlled. Multiplexed gratings, consisting of multiple harmonic grating features, show multiplet resonance modes that can be independently adjusted. This offers flexibility in designing resonance characteristics for various potential applications in nonlinear optics and controlling/enhancement of light-matter interactions, e.