Highly Selective CMOS-Compatible Mid-Infrared Thermal Emitter/Detector Slab Design Using Optical Tamm-States

Abstract

In this work, we propose and evaluate a concept for a selective thermal emitter based on Tamm plasmons suitable for monolithic on-chip integration and fabrication by conventional complementary metal oxide semiconductor (CMOS)-compatible processes. The original design of Tamm plasmon structures features a purely one-dimensional array of layers including a Bragg mirror and a metal. The resonant field enhancement next to the metal interface corresponding to optical Tamm states leads to resonant emission at the target wavelength, which depends on the lateral dimensions of the bandgap structure. We demonstrate the application of this concept to a silicon slab structure instead of deploying extended one dimensional layers thus enabling coupling into slab waveguides. Here we focus on the mid-infrared region for absorption sensing applications, particularly on the CO2 absorption line at 4.26 µm as an example. The proposed genetic-algorithm optimization process utilizing the finite-element method and the transfer-matrix method reveals resonant absorption in case of incident modes guided by the slab and, by Kirchhoff’s law, corresponds to emittance up to 90% depending on different choices of the silicon slab height when the structure is used as a thermal emitter. Although we focus on the application as an emitter in the present work, the structure can also be operated as an absorber providing adjusted lateral dimensions and/or exchanged materials (e.g., a different choice for metal).

Design and Analysis of a Slot Photonic Crystal Waveguide for Highly Sensitive Evanescent Field Absorption Sensing in Fluids

“…The small footprint of the above-mentioned devices presents opportunities for dense arrays of sensing elements and a lab-on-chip device. However, they suffer from a lack of integrated light source and WG coupling [ 1 , 17 , 25 ]. This situation might be improved by increasing the WG height, as various integrated coupling devices (taper, resonant emitters, etc.)…”

“…Therefore, a short waveguide is more favorable. However, for applications such as coupling to an integrated infrared emitter [17], the utilization of a rather thick slab waveguide would facilitate efficient coupling. Simultaneously, the mode is well confined into the Si-slab in this case, but features a low evanescent field ratio (EFR).…”

“…In this work, we are interested in determining a mode to enhance the light-matter interaction of a photonic crystal WG mode by a fluid analyte in a rather thick slab. In such a way, one can also facilitate the efficient coupling of polarized light from an integrated infrared emitter [17]. The photonic crystal waveguide mode features a high confinement of the electric field inside the Si slab.…”

Impact of Different Metals on the Performance of Slab Tamm Plasmon Resonators

“…Despite the very feasible fabrication of TP structures, the layered design is very difficult to integrate into an on-chip sensor system, as efficient coupling to a waveguide is required. In order to address this issue, we recently proposed a concept utilizing TP structures in a slab scenario, so called slab Tamm plasmon (STP) structures [13], as illustrated in Figure 1a,b. They feature good compatibility with standard complementary metal-oxide-semiconductor (CMOS) fabrication processes and, at the same time, facilitate inherent coupling to a dielectric slab waveguide.…”

“…They feature good compatibility with standard complementary metal-oxide-semiconductor (CMOS) fabrication processes and, at the same time, facilitate inherent coupling to a dielectric slab waveguide. Etching laterally exactly defined areas into the silicon slab creates regions with alternating indexes of refraction forming a Bragg mirror or, alternatively, an aperiodic bandgap structure [13,14]. In order to keep the analogy to conventional 1D-TP layers, we refer to these regions as layers.…”