The detection of infrared radiation is of great interest for a wide range of applications, such as absorption sensing in the infrared spectral range. In this work, we present a CMOS compatible pyroelectric detector which was devised as a mid-infrared detector, comprising aluminium nitride (AlN) as the pyroelectric material and fabricated using semiconductor mass fabrication processes. To ensure thermal decoupling of the detector, the detectors are realized on a Si₃N₄/SiO₂ membrane. The detectors have been tested at a wavelength close to the CO₂ absorption region in the mid-infrared. Devices with various detector and membrane sizes were fabricated and the influence of these dimensions on the performance was investigated. The noise equivalent power of the first demonstrator devices connected to a readout circuit was measured to be as low as $5.3\times {10}^{-9}\mathrm{W}/\sqrt{\mathrm{Hz}}$ .

It has been recently hypothesized that peripheral microvascular dysfunction may contribute to atherosclerotic damage (AD) in diabetic patients. In order to test this hypothesis, we assessed forearm skin post-occlusive reactive hyperaemia (skin-PORH),

Proper optimization of a photonic structure for sensing applications is of extreme importance for integrated sensor design. Here we discuss on the definition of suitable parameters to determine the impact of photonic structure designs for evanescent-wave absorption sensors on the achievable resolution and sensitivity. In particular, we analyze the most widespread quantities used to classify photonic structures in the context of sensing, namely the evanescent-field ratio (or evanescent power factor) and the confinement factor Γ. We show that, somewhat counterintuitively, the confinement factor is the only parameter that can reliably describe the absorption of the evanescent-field in the surrounding medium, and, by quantifying the discrepancy between the two parameters for a set of realistic photonic structures, we demonstrate that using the evanescent-field ratio can lead to a wrong classification of the performance of different structures for absorption sensing. We finally discuss the most convenient simulation strategies to retrieve the confinement factor by FEM simulations.

The field of mid-infrared (MIR) plasmonics has shown great potential applications in spectroscopic sensing, infrared light sources and detectors. MIR plasmonic materials that are compatible with common fabrication processes may enable cost-effective and reliable plasmonic device platforms. In this work, we examined aluminium metal (Al), gold-tin (AuSn) and titanium-tungsten (TiW) alloys regarding their usability for surface plasmon polariton (SPP) excitation in the MIR regime using a grating configuration. The angle dependence and the influence of varying depths of gratings were numerically and experimentally studied for the chosen materials. The structures were fabricated on eight-inch silicon (Si) substrates and characterized with a free-beam reflection measurement setup in the MIR regime. The fabricated gratings show narrow resonance dips, which are in good agreement with the simulations, revealing that Al, AuSn and TiW alloys are reliable plasmonic materials for MIR plasmonic devices.

Sensing of gases is a promising area for applications of photonic sensor devices that operate in the mid-infrared spectral range. We present a numerical investigation of slot waveguides for evanescent field sensing of CO₂. The sensor platform is a poly-silicon slot waveguide on silicon dioxide, where both layers are deposited on a standard silicon substrate. The evanescent field ratio, which is a crucial parameter for the sensing performance of the waveguides, was determined and values as high as 42% were obtained.