In the last two decades attosecond pulses, driven by high harmonic generation, have become an indispensable tool in ultrafast science. However their usefulness is limited by both the highest achievable photon energy, and by the highest achievable flux. Both these limitations can potentially be circumvented using synthesized laser fields.
We report the generation of attosecond pulses with...
Recently integrated THz detectors based on nonlinear polymers have shown high-sensitivity electric field measurements well-suited for quantum sensing. To expand its application for example to telecommunications a platform combining the ability of detection and emission of signals in the THz-frequency range is required. Since optical rectification - the typical nonlinear THz generation...
Cooperative effects among electric dipoles lead to drastic changes in photon emission processes. Particularly, two types of cooperative emission, namely superfluorescence (SF) and spontaneous amplified emission (ASE), dominate the emission process from highly excited materials. Here, we investigated the photoluminescence (PL) dynamics in halide perovskite giant nanocrystals to scrutinize the...
Optical antennas have been widely used for manipulating single-molecule emission properties, including intensity, lifetime, spectrum, or directivity. Investigation of all these properties with high accuracy requires precise positioning of single molecules around the antennas, something experimentally challenging. Here, we make use of DNA origami as a breadboard to control the interactions...
To approach the regime of single electron spectroscopy, we developed an asymmetric lens setup that makes the THz far-field resolution of single, strongly subwavelength meta-atoms possible.
Measuring the coupling of optical modes in complementary split-ring resonators (cSRRs) to two dimensional electron gases (2DEGs), we report normalized coupling ratios of up to $ \frac{Ω}{𝜔} =0.6$ in an...
We experimentally and theoretically investigate the robustness of fermionic superfluidity to spin-dependent dissipation in a unitary Fermi gas. We measure the influence of local, controllable particle loss on the superfluid flow that occurs at a quantum point contact connecting two superfluid reservoirs. This flow is characterized by a non-Ohmic current-bias relation due to multiple Andreev...
Quantum computers require scalability as a key ingredient in order to perform complex and reliable calculations. A promising platform is the so called QCCD architecture, in which ion traps have multiple zones dedicated to specific quantum operations. In this perspective, I will describe work performed on a Paul trap which improves the control over multiple species ion crystals, including...
Frequency dissemination in phase-stabilized optical fiber networks has become a state-of-the-art tool for metrological frequency comparisons and precision measurements. The recently established Swiss frequency metrology network spanning 456 km of fibers connects METAS to the University of Basel and ETH Zurich. This network enables dissemination of optical frequencies, referenced to the...
Strong coupling of a cavity photon to an exciton in semiconductors leads to the formation of exciton-polaritons, light-matter quasiparticles that can undergo Bose-Einstein condensation (BEC). Patterning a length-tunable cavity by Focused Ion Beam milling allows engineering potential landscapes to trap these condensates and emulate different Hamiltonians. Here, we investigate a 1D polariton...
We study Ramsey-type pulsed interrogation in a micro-fabricated Rb vapor cell for novel miniature atomic clocks called the $\mu $POP clock. Pulsed interrogation reduces light shift effects, allowing for improved long-term stability. The exploitable Ramsey free evolution time and thus the achievable Ramsey signal and clock stability are limited by the $\approx$ 4 – 5 kHz relaxation rates of the...
Three-level atomic systems coupled to light have the capacity to host dark states. We study a system of V-shaped three-level atoms coherently coupled to the two quadratures of a dissipative cavity. The interplay between the atomic level structure and dissipation makes the phase diagram of the open system drastically different from the closed one. It leads to the stabilization of a continuous...
I will present the results obtained with our cavity-QED experiment, where we trap fermionic Lithium atoms in an optical resonator to perform quantum simulations.
I will focus on the simulation of random spin models with long-range spin-exchange interactions. We implement these models by trapping a chain of atoms with tunable random transition frequencies in a cavity. The tunability is...
