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Direct thermal testing of aperiodic all-dielectric structures is presented, and its high-Q and emissivity properties are experimentally demonstrated for carbon dioxide ( CO 2) gas sensing applications. Using a 7-layer dielectric stack consisting of alternating layers of silicon (Si) and silicon dioxide ( SiO 2), backed by a metallic ground plane, an emissivity of 0.7 and a Q-factor of 113 are achieved at 70 ° C. Although this structure was already proposed in the literature, this is the first time direct thermal testing is reported, thereby showing narrowband emission properties of such structures when heated above room temperatures. An all-dielectric stack is thus found to be a simple, deposition-based structure that does not require any lateral mask preparation as frequency selectivity is achieved using an aperiodic arrangement of alternating dielectrics with contrasting permittivity. Superior performance over the periodically stacked structure is also demonstrated using numerical examples.

A conductor-backed dielectric metasurface thermal emitter at mid-IR frequencies with narrowband emissivity is experimentally demonstrated. The metasurface emitter consists of a high permittivity silicon resonator on top of a ground plane, whose resonant mechanism is explained using image theory. The resonator, placed close to a copper ground plane, is designed to produce a magnetic resonance, resulting in a low-profile device with a single emission peak in its subwavelength frequency range. The thermal emitter is next fabricated using common CMOS processes. Frequency dependent optical constants of plasma-enhanced chemical vapor deposited films of Si, SiO 2, and evaporated Cu are also reported in the mid-IR range. Narrowband thermal emission is successfully obtained at around 7.22 μ m (41.5 THz), which corresponds to the absorption band of SO 2. The Q-factor of about 37 is achieved with a peak emissivity of 0.65, which is significantly higher compared to the reported Q-factors of state-of-the-art plasmonic resonators.

A tunable spatio-temporal Talbot imaging phenomenon is presented. This phenomenon is based on the radiation properties of an array of beam-steered metamaterial composite right-/left-handed leaky-wave antennas, which is excited by a modulated pulse. The scanning law property of these antennas is exploited to achieve off-axis radiation, which leads to a tunable Talbot distance, as a function of the input pulse modulation frequency. The proposed Talbot phenomenon is analyzed theoretically, taking into account the aberrations produced by higher-order terms present in the free-space transfer function. Numerical simulations confirm the self-imaging and pulse multiplication effects and their tunability capabilities as a function of frequency. Finally, the experimental results are included to confirm the phenomenon predicted.

The existence of solitons in SiO2–Ag–SiO2 and Ag–SiO2–Ag plasmonic waveguides (PWGs) is investigated using a nonlinear transmission line approach. Both the SiO2–Ag–SiO2 and the Ag–SiO2–Ag, the former in its TM even mode and the latter in its odd mode, are shown to support bright solitons as solutions to the nonlinear Schrodinger equation. The SiO2–Ag–SiO2 even mode has low left-handed (LH) loss but is undesirably mixed with a right-handed mode, while the Ag–SiO2–Ag odd mode exhibits low-loss pure LH characteristics and is therefore the most suited mode for soliton propagation. Soliton PWGs may find applications in compact switching, pulse shaping, and pulse compressing devices.