Schuessler combines optical frequency combs with cavity-enhanced and mid-IR spectroscopy for ultrasensitive trace-gas and isotopic detection, and runs ion-trap precision mass/laser spectroscopy of exotic species. In the broader landscape of NV-centre ensemble quantum sensing (DEER, nano-NMR, T1 relaxometry) operating near pT/sqrt(Hz) sensitivity, this work is a comb-metrology counterpart to spin-based chemical sensing.

Treps leads the Multimode Quantum Optics group at LKB. Research directions: (1) Multimode quantum frequency combs — synchronously pumped OPO (SPOPO) generates entangled networks of squeezed modes with configurable graph structure; first demonstration of quantum frequency comb with multimode squeezing (PRL 2012); (2) Quantum-enhanced multiparameter estimation — quantum Fisher information and multimode squeezing for simultaneous beyond-shot-noise parameter estimation (e.g., frequency comb spectral centroid and energy, PRX 2020); (3) Non-Gaussian quantum states — heralded generation of non-Gaussian cluster states for CV quantum computing; (4) Quantum metrological inequalities — relating non-locality to parameter estimation. Spin-off: Cailabs (multimode fiber light-shaping for telecom and industrial lasers). Co-director of QICS. ERC-funded.