High‐performance integrated mid‐infrared filter arrays

Hakkel, Kaylee D.; Elst, Don M. J. van; Petruzzella, Maurangelo; Ebermann, Martin; Pagliano, Francesco; Klinken, Anne van; Fiore, Andrea

doi:10.1049/ell2.12626

Cited by 2 publications

(1 citation statement)

References 13 publications

(17 reference statements)

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“…The use of thin metals as opposed to previously implemented distributed Bragg reflectors [6][7][8][9] or subwavelength gratings [10,11] in optical gas sensors has been growing in recent decades due to the MTF's advantages, such as an infinitely variable reflectivity of the mirror adjusted by the films' thickness, a comparatively less complex fabrication process, as well as an extraordinarily high reflectivity in VIS [12]. Previously held back by the higher absorption of metal materials, which DBR and SWG do not suffer from, MTFs are being used more often in optical sensor applications these days [13,14].…”

Section: Introductionmentioning

confidence: 99%

Characterization of Thin AlN/Ag/AlN-Reflector Stacks on Glass Substrates for MEMS Applications

Behl,

Behlert,

Seiler

et al. 2024

Micro

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Thin metal layers such as silver (Ag) are being utilized for various optical and plasmonic applications as well as for electrical purposes, e.g., as transparent electrodes in display devices or solar cells. This paper focuses on optical MEMS applications such as the Fabry–Pérot interferometer (FPI). Within such filters, reflector materials such as distributed Bragg reflectors (DBRs) or subwavelength gratings (SWGs) have been widely used so far, whereas metallic thin films (MTFs) were limited in application due to their comparatively higher absorption. In this paper, thin sputtered Ag layers with thicknesses of 20, 40 and 60 nm on glass substrates have been investigated, and it is shown that the absorption is very low in the visible spectral range (VIS) and increases only in near-infrared (NIR) with increasing wavelength. Thus, we consider Ag-thin layers to be an interesting reflector material at least for the VIS range, which can be easily fabricated and integrated. However, Ag is not inert and stable when exposed to the atmosphere. Hence, it needs a passivation material. For this purpose, AlN has been chosen in this contribution, which can be deposited by sputtering as well. In this contribution, we have chosen thin AlN layers for this purpose, which can also be deposited by sputtering. Thus, various AlN/Ag/AlN-reflector stacks were created and patterned by lift-off technology preferably. The fabricated reflectors were characterized with respect to adhesion, stress, cohesion, homogeneity, and most importantly, their optical properties. It was found that the thickness of the AlN can be used to adjust the reflectance–transmittance ratio in the VIS range, and influences the adsorption in the NIR range as well. Based on the measured values of the reflectors with 40 nm Ag, an exemplary transmission filter characteristics has been predicted for a wavelength range from 400 to 800 nm. Both the maximum transmittance and the full width at half maximum (FWHM) can be tuned by variation of the AlN thickness from 20 to 60 nm.

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Section: Introductionmentioning

confidence: 99%

Characterization of Thin AlN/Ag/AlN-Reflector Stacks on Glass Substrates for MEMS Applications

Behl,

Behlert,

Seiler

et al. 2024

Micro

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Multiparametric Methods for Rapid Classification of Diesel Fuel Quality Used in Automotive Engine Systems

Borecki,

Geca,

Zan

et al. 2024

Energies

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Fuels should behave appropriately in all sections of the engine system: the engine, fuel delivery system, and tank. Fuel quality can be linked to the following three crucial areas: performance, fitness for current use, and stability. Classical methods of diesel fuel examination mostly rely on the absolute value measurement of one specific parameter while stabilizing outside conditions. In contrast, multiparametric methods depend on simultaneously measuring a set of parameters. Therefore, multiparametric methods open the possibility of intriguing new examinations and classifications of diesel fuel quality while raising specific issues relating to the instrumentation and construction of sensing devices. This paper presents a review, based on the published literature and the authors’ research, of the current state-of-the-art multiparametric methods for rapid diesel fuel quality classification and related instrumentation, systematizing the various types of methods from the point of view of the principles of their operation. The main conclusion is that different measuring procedures use similar methods of data processing. Moreover, the heavy, costly, and complex devices that enable standard examinations can be converted to simpler devices in the future, whose cost of use is significantly lower. However, to achieve this, progress in electronic devices is required.

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High‐performance integrated mid‐infrared filter arrays

Cited by 2 publications

References 13 publications

Characterization of Thin AlN/Ag/AlN-Reflector Stacks on Glass Substrates for MEMS Applications

Characterization of Thin AlN/Ag/AlN-Reflector Stacks on Glass Substrates for MEMS Applications

Multiparametric Methods for Rapid Classification of Diesel Fuel Quality Used in Automotive Engine Systems

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