Cryogen-free low-temperature BLS spectrometer

• Subject Area: Condensed Matter Physics
• Term: Funded in 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 567186839

Spin waves are the fundamental excitations of the spin system in a magnetically ordered material, and magnons are their quasiparticles. Brillouin light scattering spectroscopy (BLS) is now an established tool for characterizing spin waves. BLS refers to the inelastic scattering of light by spin waves and offers several advantages: the ability to map the intensity of spin waves with spatial resolution and high sensitivity, as well as the potential for simultaneous detection of frequency and wave vector. The field of magnonics is currently attracting great interest within the scientific community, particularly due to its relevance to fundamental questions of spin dynamics and the potential of spin waves for information technology. Recent studies are expanding magnonics to cryogenic temperatures. This development is driven by research on strongly coupled light-spin hybrid systems for quantum computing, which approach the quantum limit of excitation and often even require integration with superconducting electronics (fluxonics). The cryogen-free low-temperature BLS spectrometer enables fully computer-controlled and automated data acquisition, along with extensions for both established and newly developed measurement methods. This approach eliminates the need for additional, stand-alone experimental setups in many cases, optimizing the use of available resources. The low-temperature system operates without cryogens, significantly reducing ongoing operational cost. The measurement system supports diverse collaborations, both within TU Braunschweig and with PTB, at the highest level of instrumentation. It is essential for implementing the research concept of the newly established "Cryogenic Quantum Electronics" group at the Institute for Electrical Metrology and Fundamental Electrical Engineering at TU Braunschweig, which was formed following a new appointment in July 2024. The system complements the existing infrastructure of the Laboratory for Emerging Nanometrology (LENA) and is of high relevance for follow-up projects within the Excellence Cluster EXC-2123 QuantumFrontiers. Additionally, it will facilitate the smooth transfer of the applicant’s activities from Vienna to Braunschweig and, due to its expandability, will serve as a modern experimental platform for various collaborations.

• DFG Programme: Major Research Instrumentation
• Major Instrumentation: Kryogenfreies Tieftemperatur-BLS-Spektrometer
• Instrumentation Group: 0150 Geräte zur Messung der magnetischen Materialeigenschaften
• Applicant Institution: Technische Universität Braunschweig
• Leader: Professor Dr. Oleksandr Dobrovolskiy