Triple Narrowband Mid-Infrared Thermal Emitter Based on a Au Grating-Assisted Nanoscale Germanium/Titanium Dioxide Distributed Bragg Reflector: Implications for Molecular Sensing

Abstract

Mid-infrared (MIR) light sources with selective multiple narrowband and minimal angular dependence have desired properties for practical sensing applications. In this work, a triple narrowband MIR thermal emitter is realized by a hybrid structure composed of gold (Au) gratings on top of an alternate stacking germanium/titanium dioxide (Ge/TiO 2 )-distributed Bragg reflector (DBR) and a Au reflector. Upon transverse-electric (TE)-polarized light illumination, three types of resonant modes including the hybridized Tamm plasmon polaritons (TPPs), the gap-cavity (GC) mode, and the middle-guided (MG) mode were excited simultaneously. While the hybridized TPPs are mainly determined by the composed nanolayers of the DBR, our results show that the GC mode has a strong dependence on the top-Gelayer thickness as well as on the gap distance between metallic stripes, and the MG mode mainly relies on the grating periodicity. In addition, both the hybridized TPPs and the GC mode exhibit a small wavelength deviation when varying the oblique incident angle. Thus, these two modes are applied to contribute triple radiation peaks at the wavelength range of 3−6 μm upon heating of the device. The distinct geometric dependence among the excited modes in the hybrid structure provides an additional degree of freedom in independently adjusting the spectral positions of the emission bands. Such a selective multiwavelength, narrowband, and small angular-dependent MIR light source is promising for enhancing the accuracy in discrimination of molecular fingerprint.

Decaffeination and improvement of taste, flavor and health safety of coffee and tea using mid-infrared wavelength rays

“…Even though a variety of mid-IR emitters are now available (e.g., silicon photonic devices ( CMOS Emerging Technologies, 2012 ), cascade lasers (quantum and inter-band) ( Jung et al., 2017 ), non-cascade-based lasers, chalcogenide fiber-based photonic devices ( Sincore et al., 2018 ), suspended-core tellurium-based chalcogenide fiber photonic devices ( Wu et al., 2018 ), and infrared thermal emitters ( Hsiao et al., 2021 ), these emitters are not as cost-effective as MIRGA, and also have not been tested in a domestic setting or with foods.…”

Selective Properties of Mid-Infrared Tamm Phonon-Polaritons Emitter with Silicon Carbide-Based Structures

“…It has been demonstrated that gratings can be stacked on top of DBR to enhance the polarization-correlation emission rate, selective resonance and high radiation directional property [33,36]. Figure 7 shows a diagrammatic drawing of the photonic Tamm structure, which is composed of a one-dimensional (1D) periodic SiC grating deposited onto a ZnSe/Ge-based DBR (consisting of 5 pairs of ZnSe/Ge alternances with λ/4 layer thickness and center wavelength λ Bragg = 12 µm) with an additional Ge spacer layer.…”

Tamm Plasmon-Mediated Tunable Absorption Switching in Atomically Precise Pt17 Nanoclusters for Nonlinear Photonic Applications

“…TPPs are considered as practical substitutes for traditional surface plasmons due to lower dielectric loss, longer propagation distance, and higher field strength . These capabilities qualify such structures to be used in fluorescence control, , sensors, , absorbers, , low-threshold lasing, narrow-band thermal emitters, , and so forth.…”