Universität Stuttgart

Permanent URI for this communityhttps://elib.uni-stuttgart.de/handle/11682/1

Browse

Filters

2022 - 20242

Settings

Subject: search.filters.subject.530Subject: search.filters.subject.620Start date: 2020Author: search.filters.author.Giessen, HaraldAuthor: search.filters.author.Hentschel, Mario

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    ItemOpen Access
    Predicting concentrations of mixed sugar solutions with a combination of resonant plasmon-enhanced SEIRA and principal component analysis
    (2022) Pfezer, Diana; Karst, Julian; Hentschel, Mario; Giessen, Harald
    The detection and quantification of glucose concentrations in human blood or in the ocular fluid gain importance due to the increasing number of diabetes patients. A reliable determination of these low concentrations is hindered by the complex aqueous environments in which various biomolecules are present. In this study, we push the detection limit as well as the discriminative power of plasmonic nanoantenna-based sensors towards the physiological limit. We utilize plasmonic surface-enhanced infrared absorption spectroscopy (SEIRA) to study aqueous solutions of mixtures of up to five different physiologically relevant saccharides, namely the monosaccharides glucose, fructose, and galactose, as well as the disaccharides maltose and lactose. Resonantly tuned plasmonic nanoantennas in a reflection flow cell geometry allow us to enhance the specific vibrational fingerprints of the mono- and disaccharides. The obtained spectra are analyzed via principal component analysis (PCA) using a machine learning algorithm. The high performance of the sensor together with the strength of PCA allows us to detect concentrations of aqueous mono- and disaccharides solutions down to the physiological levels of 1 g/L. Furthermore, we demonstrate the reliable discrimination of the saccharide concentrations, as well as compositions in mixed solutions, which contain all five mono- and disaccharides simultaneously. These results underline the excellent discriminative power of plasmonic SEIRA spectroscopy in combination with the PCA. This unique combination and the insights gained will improve the detection of biomolecules in different complex environments.
  • Thumbnail Image
    ItemOpen Access
    Positional accuracy of 3D printed quantum emitter fiber couplers
    (2024) Weber, Ksenia; Thiele, Simon; Hentschel, Mario; Herkommer, Alois; Giessen, Harald
    Precise positioning of optical elements plays a key role in the performance of optical systems. While additive manufacturing techniques such as 3D printing enable the creation of entire complex micro‐objectives in one step, thus rendering lens alignment unnecessary, certain applications require precise positional alignment of the printing process with respect to the substrate. For example, in order to efficiently couple quantum emitters to single‐mode fibers, which is a crucial step in the development of real world quantum networks, precise alignment between the emitter, the coupling optics, and the single‐mode fiber is of utmost importance. In this work, the positioning accuracy of a Photonics Professional GT (Nanoscribe GmbH) 3D printing machine is evaluated by using the integrated piezo stage to align to gold markers that is manufactured via e‐beam lithography. By running a statistical analysis of 38 printing cycles, a mean positional error of only 80 nm is determined. Additionally, an entire system is 3D printed that can couple quantum emitters to optical single‐mode fibers. Examining the focal spot of the 3D printed micro‐optics, a positional accuracy of ≈ 1 µm in all three dimensions is found, as well as excellent quality of the focal spot.