Working on this experiment: David Latorre Bastidas, André Wenzlawski

Ultra-cold atoms are one of todays most anticipated objects of research, with applications ranging from inertial sensing to gravitational wave detection. Most of these require optical systems for e.g. laser-cooling and sensing of the atoms, as well as vacuum systems to shield the sensitive atoms from the environment. In recent years, more and more experiments shifted from solely laboratory-based away to miniaturized field- and space-borne setups.

Miniaturized and robust optical systems were demonstrated in various experiments, as well as in previous works of this working group. On the other hand, vacuum systems mostly still consist of bulky commercial setups requiring a lot of space, as well as skilled personnel to be operated. That is why, we also work towards developing miniaturized, robust and fully-integrated ultra-high vacuum chambers for quantum optical experiments.

ZEROVAK

In a collaboration between UHH Hamburg and JGU Mainz, the DLR-funded project ZEROVAK aims to provide a novel approach of miniaturized Zerodur based vacuum systems for quantum technology applications. Born from the experience of using Zerodur as a material for compact optical systems, the motivation established to develop miniaturized vacuum systems made of Zerodur to create an unprecedented connectivity between optical and vacuum systems. Such a system based fully on Zerodur would enable a homogenous, thermally stable and highly miniaturizable overall system without any mismatches in coefficients of thermal expansion (CTE).

Using Zerodur as the material of choice for vacuum systems offers several additional advantages. For instance, Zerodur has an extremely low helium permeability, which is particularly beneficial for maintaining ultra-high vacuum (UHV) in stand-alone systems, i.e., those operating without active pumping. In addition, Zerodur is both non-magnetic and electrically insulating, thereby suppressing the generation of unwanted magnetic fields inside the chamber, whether from eddy currents or from the distortion of external magnetic fields.

Our goal within this project is to develop a miniaturized quantum sensor based on cold atoms for operation in harsh environments. To achieve that goal, the ZEROVAK project first focuses on developing a miniaturized and fully integrated stand-alone vacuum chamber for the creation of a magneto optical-trap (MOT) of Rubidium-87 atoms. The chamber incorporates atomic dispensers, non-evaporable getters, a MOT grating chip and nine optical accesses. A printed circuit board (PCB) is placed outside the chamber for the generation of the needed magnetic field for MOT.

The chamber uses anti-reflection–coated Zerodur windows, which are glued to the chamber with a low-outgassing epoxy. It also features a conical flange connection to a commercial vacuum system, allowing UHV conditions to be created inside the chamber. In this context, we are further investigating Zerodur-to-glass and Zerodur-to-metal connections. These not only improve the performance of our integrated vacuum chamber but also open up a new toolbox for connecting complex glass-ceramic–based chambers to commercial vacuum technology.

Finally, the chamber does not include any electrical feedthroughs, which often limit the achievable vacuum in stand-alone systems. Instead, both rubidium dispensers and non-evaporable getters are activated externally using high-power blue light. This optical activation eliminates the need for direct electrical connections, reducing outgassing sources and simplifying the overall chamber design.

Looking ahead, we aim to develop a fully integrated setup—combining the vacuum chamber, laser system, and control electronics—within a footprint no larger than a shoebox. Such a compact and portable system will enable operation in real-life scenarios and even in harsh environments, greatly expanding its range of applications.

Bachelor / Master Theses

We always offer projects both for bachelor and master theses. At the moment the following projects are available in our lab:

  • Characterization of a Zerodur vacuum chamber for quantum optical experiments
    • As part of our efforts to develop a stand-alone vacuum system for quantum optical experiments, we plan to use a magneto-optical trap (MOT) of rubidium atoms to measure the pressure inside the chamber. In this thesis project, you will work on optimizing an experimental sequence for pulsed dispensing of rubidium using high-power blue light, enabling the generation of a MOT. In addition, you will contribute to the design and characterization of the imaging system required for atomic detection—and thus for extracting the pressure readout.
  • Development of a miniaturized laser system and control electronics for the generation of a magneto optical trap (MOT)
    • To advance the development of a miniaturized, deployable quantum sensor, we aim to design and build a compact laser system and control electronics capable of providing all required functionalities. In this thesis project, your task will be to design and/or assemble a system that delivers the necessary optical frequencies. As part of this work, you will also characterize a frequency modulation spectroscopy (FMS) and/or modulation transfer spectroscopy (MTS) setup, which is essential for tuning the lasers to the correct atomic transition frequencies.

If you are interested in joining our team as a bachelor or master student, please contact Prof. Patrick Windpassinger, Dr. André Wenzlawski or PhD student David Latorre Bastidas.