3.3 - A miniaturized MID-IR-Spectrometer based on a linear variable filter and pyroelectric line array – Monitoring oil condition

A Portable Infrared Attenuated Total Reflection Spectrometer for Food Analysis

“…Another limitation to consider is the limited and variable spectral resolution across the detected wavelength band of approximately 10–30 cm –1 . 23 , 24 In a study conducted by Wiesent et al, 25 the use of MIR emitters and LVFs in conjunction with PLAD was explored to monitor oil conditions. The authors emphasized that while the resolution of the compact spectrometer was lower compared to FT-IR, it still provided the capability to accurately predict specific parameters such as oxidation and total base number (TBN).…”

“…In fact, the predictive performance of the compact spectrometer indeed matched that of the FT-IR approach, as evidenced by R 2 values of 0.972 and 0.984 for oxidation and TBN, respectively. 25 Thus, a wide variety of analytical applications, especially when analyzing liquid or solid samples, that do not require a high spectral resolution may benefit from such devices, as in the presently investigated scenario focused on food quality and safety.…”

Miniaturized short-wavelength infrared spectrometer for diffuse light applications

“…Wedge filter-based spectrometers, which operate on the same principle as thin-film interference bandpass filters, have been studied as one route to spectrometer miniaturization 18 , 22 – 24 In a wedge filter, the interference layer thickness varies from one side to the other across the filter. This results in a passband center wavelength that varies with position.…”

High‐performance integrated mid‐infrared filter arrays

“…This has been demonstrated using plasmonic filters and LVFs. However, plasmonic filters display a relatively large linewidth (exceeding 1 µm [9], depending on the wavelength range), while LVFs are best suited for a linear geometry and a very large filter array [5,6]. As an alternative approach, MEMS tunable MIR filters have been investigated [10], but they are subject to vibrations and their tuning range is typically more limited.…”

“…Gas sensing systems are important especially to ensure safety, for example, for the detection of inflammable and toxic gases, monitoring greenhouse gases and for measuring the presence of volatile organic compounds (VOCs) for air quality control, thereby opening a large global market [3]. Besides the applications in gas sensing, MIR sensing is also interesting for other type of materials, for example, for classifying black plastics [4] and for monitoring oil conditions [5] and soil health [7].…”