In this paper we review some metasurfaces with negative values of effective refractive index, as scaffolds for a new generation of surface plasmon polariton-based biological or chemical sensors. The electromagnetic properties of a metasurface may be tuned by its full immersion into analyte, or by the adsorption of a thin layer on it, both of which change its properties as a plasmonic guide. We consider various simple forms of plasmonic crystals suitable for this purpose. We start with the basic case of a freestanding, electromagnetically symmetrical plasmonic slab and analyze different ultrathin, multilayer structures, to finally consider some two-dimensional “wallpaper” geometries like split ring resonator arrays and fishnet structures. A part of the text is dedicated to the possibility of multifunctionalization where a metasurface structure is simultaneously utilized both for sensing and for selectivity enhancement. Finally we give an overview of surface-bound intrinsic electromagnetic noise phenomena that limits the ultimate performance of a metasurfaces sensor.

The key equipment for performing aerodynamic testing of objects, such as road and railway vehicles, aircraft, and wind turbines, as well as stationary objects such as bridges and buildings, are multichannel pressure measurement instruments (pressure scanners). These instruments are typically based on arrays of separate pressure sensors built in an enclosure that also contains temperature sensors used for temperature compensation. However, there are significant limitations to such a construction, especially when increasing requirements in terms of miniaturization, the number of pressure channels, and high measurement performance must be met at the same time. In this paper, we present the development and realization of an innovative MEMS multisensor chip, which is designed with the intention of overcoming these limitations. The chip has four MEMS piezoresistive pressure-sensing elements and two resistive temperature-sensing elements, which are all monolithically integrated, enabling better sensor matching and thermal coupling while providing a high number of pressure channels per unit area. The main steps of chip development are preliminary chip design, numerical simulations of the chip’s mechanical behavior when exposed to the measured pressure, final chip design, fabrication processes (photolithography, thermal oxidation, diffusion, layer deposition, micromachining, anodic bonding, and wafer dicing), and electrical testing.

The existing instruments for aerodynamic pressure measurements are usually built around an array of discrete pressure sensors, placed in the same housing together with a few discrete temperature sensors. However, this approach is limiting, especially regarding miniaturization, sensor matching, and thermal coupling. In this work, we intend to overcome these limitations by proposing a novel MEMS multisensor chip, which has a monolithically integrated matrix of four piezoresistive MEMS pressure-sensing elements and two resistive temperature-sensing elements. After finishing the preliminary chip design, we performed computer simulations in order to assess its mechanical behavior when measured pressure is applied. Subsequently, the final chip design was completed, and the first batch was fabricated. The used technological processes included photolithography, thermal oxidation, diffusion, sputtering, micromachining (wet chemical etching), anodic bonding, and wafer dicing.

We investigated different biomimetic structures inspired by natural brochosome powders which appear on the bodies and wings of leafhoppers (insects from the Cicadellidae family). All structures we analyzed are roughly spherical, with diameters 200 nm to 1000 nm, with a core and a shell made of different materials and the core perforated with subwavelength holes with diameters of the order of tens of nanometers. We extended the range of possible designs, geometries and materials of synthetic brochosomes, inspired by their natural counterparts found as powders secreted by various species of leafhoppers. We performed simulation of the optical properties of the structures using the finite element method. We found out that our approach ensures the design of highly efficient omnidirectional ultra-antireflective diffractive powders with subwavelength apertures. The reflectivity of 600 nm diameter holey spheres does not exceed 0.02% in 500-600 nm range. We showed that planar arrays of plasmonic-based artificial brochosomes exhibit a rich optical behavior, including effective refractive index below unity and even below zero at longer wavelengths. Such metamaterial-like behavior contributes to the multifunctionality of our synthetic brochosomes which can already serve as antireflective, superhydrophobic and highly porous structures controllable by design. This kind of versatility shows potentials for numerous practical uses. A major part of the novel functionalities stems from the use of nanocomposites containing free-electron conductors (plasmonic materials). Thus we arrived at a toolbox for the design of highly customizable antireflective layers. Potential fields of use include photodetectors, photoelectrochemistry, photocatalysis and general microoptoelectromechanical (MOEMS) systems.

In this paper we present the concept of a novel MEMS multisensor instrument for aerodynamic pressure measurements, and discuss the main aspects of its design. Designing of such instrument is a complex task, especially because of high requirements regarding miniaturization, measurement performance, the number of pressure measurement channels, and other features. The main goal of the presented work is to address these requirements in an innovative way. A novel multisensor chip, which has been designed and fabricated, is an important step towards further miniaturization and higher measurement performance of aerodynamic pressure measurement instruments. Multisensor modules, which contain the multisensor chips and accompanying connections and circuitry, enable modularity and reconfigurability of the instrument. The novel hardware architecture has a separate signal path for each of the pressure channels, and is capable of synchronous pressure measurement on all channels. Digital signal processing enables high measurement performance, and can be used to implement fault detection capabilities. The final goal of the presented work is to combine these concepts into a high-performance and innovative instrument for aerodynamic testing, which is a useful tool for several scientific and industrial fields.