We initiate a fundamental study of modal-plasmonic interactions in nanostructured resonance elements with the aim to develop new hybrid multiparametric sensors. The proposed hybrid sensor operates under guided-mode resonance (GMR) and surface-plasmon resonance (SPR) in unison. Numerical simulations of gold-integrated periodic resonant films show effective spectral conversions due to interplay between these mechanisms. In some cases, we find enhancements in sensitivity and attendant reduced resonance linewidths improving sensor resolution. Initial experimental results incorporating modal-plasmonic interactions in a resonant system containing a dielectric grating on a thin gold film agree qualitatively with theory. The research is important as the SPR and GMR concepts are independently the basis for commercial sensor systems with major economic impact.
Resonant leaky modes can be induced on dielectric, semiconductor, and metallic periodic layers patterned in one or two
dimensions. In this paper, we summarize their physical basis and present their applicability in photonic devices and
systems. The fundamental amplitude and phase response of this device class is presented by computed examples for TE
and TM polarizations for lightly and heavily spatially modulated gratings. A summary of potential applications is
provided followed by discussion of representative examples. In particular, we present a resonant polarizer enabled by a
single periodic silicon layer operating across 200-nm bandwidth at normal incidence. Guided-mode resonance (GMR)
biosensor technology is presented in which the dual-polarization capability of the fundamental resonance effect is
applied to determine two unknowns in a biodetection experiment. In principle, using polarization and modal diversity,
simultaneously collected data sets can be used to determine several relevant parameters in each channel of the sensor
system; these results exemplify this unique capability of GMR sensor technology. Applying the GMR phase, we show
an example of a half-wave retarder design operating across a 50-nm bandwidth at λ~1550 nm. Experimental results
using a metal/dielectric design show that surface-plasmon resonance and leaky-mode resonance can coexist in the same
device; the experimental results fit well with theoretical simulations.
We numerically study surface-plasmon (SP) mediated semiconductor light-emitting diodes (LEDs) and show that
mediation of SPs can be useful for high power LEDs in their modulation speeds and directionalities. It has been reported
that SPs can drastically enhance internal quantum efficiencies and speeds of InGaN quantum-well (QW) LEDs by letting
them dominate spontaneous emission (SE) processes. Many experimental and theoretical studies have been conducted in
this context but most of the works have dealt SE into SPs and light extraction from excited SPs separately. In particular,
there is no theoretical analysis, to our knowledge, which simultaneously considers SE into SPs on a textured metal
surface along with its extraction to outside radiation. In this presentation, we numerically study InGaN QW LEDs which
consist of 1-D metallic gratings on a p-contact electrode and an adjacent single QW emitting green light by using finite-difference
time-domain (FDTD) method. We focus on the case where the first order diffraction of SPs produces
lightwaves propagating along the surface-normal direction. SP band-edge effect on SE rate, extraction of SPs into
internal-radiation, and angular directionality of final outside-radiation are analyzed. Practical enhancement of LED
performances are discussed on the basis of the simulation results.
Strong reemission of the surface plasmons through a single subwavelength aperture is mainly caused by in-phase coupling of the surface localized electromagnetic waves to irradiative modes by periodic groove structures. By introducing a linear chirping in the groove period, we enhance the coupling effect for focusing the reemitted light in near-field region. The linear chirping in the groove structures which have monotonically decreasing period, leads to focusing the reemitted light with the length, depth, and width of the focus in order of wavelength. We show numerically that the focusing ability is dramatically affected by amount of the linear chirping, and that efficient relaying of a diverging Gaussian beam to a photonic crystal waveguide can be achieved.
We have observed experimentally photonic band gap in dispersion curves of SPPs excited at a 1-D dielectric lattice structure on a flat metal surface. The observation result is compared with theoretical result by using of the well-known calculation method of diffraction, rigorous coupled wave analysis method.
Photonic band gap interaction between surface plasmon (SP) and dielectric gratings is calculated by rigorous coupled wave analysis (RCWA). Results from the RCWA show that the reflectance goes down near to 0%, and the diffraction efficiency increases above 50% even though the modulation depth of the grating layer is less than 100nm. If the grating vector is twice of the wave vector of SP, on the other hand, the reflectance surprisingly increases up to 90% even though the resonance condition of the SP is satisfied. This photonic band gap effect at the SP resonance can be completely analyzed by the RCWA, and verified by experiment.