HES-SO Lab
HESSO is investigating the miniaturization of the THz components, which is required for future space missions.
This setup is located in the laboratory of the University of Applied Sciences and Arts Western Switzerland Valais (HES-SO) in Sion. Its focus is set to miniaturize THz time-domain spectroscopy antennas.
Engineered Samples for Terahertz Analysis
To develop and calibrate our miniaturized terahertz time-domain spectroscopy (THz-TDS) system, we have engineered a comprehensive library of standardized samples. These samples simulate a wide range of potential material compositions, allowing us to meticulously test the sensitivity, resolution, and limits of our detection system.
Our approach involves embedding various organic and inorganic molecular crystals into polymer matrices at precisely controlled concentrations. This method creates stable, homogeneous pellets with known dielectric properties, which are ideal for benchmarking terahertz performance.
Key Features of Our Sample Library:
Diverse Active Molecules: Our samples include key compounds such as L-Alanine (a simple amino acid), Ammonium Chloride (NH₄Cl) (an inorganic salt), Anthracene, and Pyrene (polycyclic aromatic hydrocarbons).
Wide Concentration Range: We study these molecules across a vast concentration spectrum, from percentage-level blends (e.g., 5%, 10%) down to trace amounts measured in parts per million (ppm), testing our system's detection thresholds.
Varied Matrix Materials: The molecules are embedded in different polymer matrices, primarily Polytetrafluoroethylene (PTFE, transparent to THz radiation) and Ultra-High-Molecular-Weight Polyethylene (UHMW-PE), to understand how the surrounding material influences the terahertz response.
Multiple Fabrication Methods: We have developed and optimized several preparation protocols (e.g., dry mixing, solution-based integration, hot-pressing) to achieve the most homogeneous distribution of the analyte within the matrix, which is critical for reliable spectroscopic results.
Precise Geometry: All samples are fabricated to specific diameters (15mm) and thicknesses (typically 1-3mm), ensuring consistent and reproducible measurement conditions.
THz Simulations
Simulations of THz pulses in the optical setup are performed HES-SO.
Bench Setup
The bench setup is based on a spectrometer from TOPTICA, the Teraflash pro. Our goal is to reduce the size of this device and it’s weight. The miniaturization of the delay line is essential for this process.
The mirror arrangement of the THz beam-path needs to be aligned. The picture shows the alignment process (red spot on the sample).
Such an alignment procedure is not possible in space. We need to develop a robust system that can be pre-aligned on the ground.
The sample is placed on an XYZ-stage to scan it in three dimensions.
Miniaturization
The antennas used for the spectroscopy are required to have a minimal footprint. The goal is to place them inside a drill.To achieve this, the application of THz lenses and different mirrors are investigated.
LIBS
The Laser Induced Spectroscopy (LIBS) is a mean to detect the nature of the matter that is analysed. A strong laser pulse is used to generate plasma. The light emited by the atoms at this instant is analysed by a spectrometer.
The specific project goal is to perform spectroscopy in a small space. One of the challenge is to send the laser pulse through a fiber and focus the beam onto the sample.
