Wideband current modulation of diode lasers for frequency stabilization.

We present a current modulation technique for diode laser systems, which is specifically designed for high-bandwidth laser frequency stabilization and wideband frequency modulation with a flat transfer function. It consists of a dedicated current source and an impedance matching circuit both placed close to the laser diode. The transfer behavior of the system is analyzed under realistic conditions employing an external cavity diode laser (ECDL) system.

Digital laser frequency and intensity stabilization based on the STEMlab platform (originally Red Pitaya).

We report on the development, implementation, and characterization of digital controllers for laser frequency stabilization as well as intensity stabilization and control. Our design is based on the STEMlab (originally Red Pitaya) platform. The presented analog hardware interfaces provide all necessary functionalities for the designated applications and can be integrated in standard 19-in.

Arrays of individually controllable optical tweezers based on 3D-printed microlens arrays.

We present a novel platform of optical tweezers which combines rapid prototyping of user-definable microlens arrays with spatial light modulation (SLM) for dynamical control of each associated tweezer spot. Applying femtosecond direct laser writing, we manufacture a microlens array of 97 lenslets exhibiting quadratic and hexagonal packing and a transition region between the two. We use a digital micromirror device (DMD) to adapt the light field illuminating the individual lenslets and present a detailed characterization of the full optical system.

Defect-Free Assembly of 2D Clusters of More Than 100 Single-Atom Quantum Systems.

We demonstrate the defect-free assembly of versatile target patterns of up 111 neutral atoms, building on a 361-site subset of a micro-optical architecture that readily provides thousands of sites for single-atom quantum systems. By performing multiple assembly cycles in rapid succession, we drastically increase achievable structure sizes and success probabilities. We implement repeated target pattern reconstruction after atom loss and deterministic transport of partial atom clusters necessary for distributing entanglement in large-scale systems.

Optimization strategies for modulation transfer spectroscopy applied to laser stabilization.

We present a general analysis for determining the optimal modulation parameters for the modulation transfer spectroscopy scheme. The results are universally valid and can be applied to spectroscopy of any atomic species requiring only the knowledge of the effective linewidth Γeff. A signal with optimized slope and amplitude is predicted for a large modulation index M and a modulation frequency comparable to the natural linewidth of the spectroscopic transition.