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Miniature Atomic vapor-Cells Quantum devices for SensIng and Metrology AppLications

Periodic Reporting for period 1 - MACQSIMAL (Miniature Atomic vapor-Cells Quantum devices for SensIng and Metrology AppLications)

Reporting period: 2018-10-01 to 2020-03-31

Sensors provide the interface between the real world and the digital world. Quantum technologies are poised to revolutionize this interface, and with it sensor-driven industries such as navigation and medical imaging.
MACQSIMAL will develop quantum-enabled sensors with outstanding sensitivity for five key physical observables: magnetic fields, time, rotation, electro-magnetic radiation and gas concentration. These sensors are chosen for their high impact and their potential to quickly advance to a product. Within MACQSIMAL all these sensors will reach TRLs between 3 and 6 and will outperform other solutions in the respective markets.
In MACQSIMAL, the common core technology in these five sensors is atomic vapor cells realized as integrated microelectromechanical systems (MEMS). First generation atomic quantum sensors exploit the collective effect of single-particles quantum coherence for extreme sensitivity to many physical quantities of interest. With the second generation, they have the potential to harness multi-particle quantum coherence for still greater sensitivity. Fabricating such atomic vapor cells as MEMS allows for high-volume, high-reliability and low-cost deployment of miniaturized, integrated sensors, critical to wide-spread adoption.
MACQSIMAL will combine state-of-the-art sensor physics with the MEMS atomic vapor cell platform for highly advanced prototypes and demonstrators and will thus contribute to kick-starting a competitive European quantum sensor industry.
Before the COVID-19 pandemic hit Europe, the main tasks of the MACQSIMAL consortium were conducted in the labs, through fabrication, assembly and testing of novel first-generation quantum sensor demonstrators. Interesting and very promising results were being acquired and the first sensors prototype building blocks have been fabricated. Quantum enhancement strategies for these quantum sensors are also being established. Currently, the COVID-19 situation in Europe has slowed down the lab work in the past months. The impact and the duration of this lab shutdown is difficult to assess at this stage.

The first tasks of MACQSIMAL were dedicated to a review of state-of-the-art developments in the field of quantum sensors, as well as a deep survey on patents related to the five target applications tackled in the project. The freedom to operate has in particular been checked for.

The atomic vapour cell designs as well as the corresponding quantum sensor prototype designs have been finalized. Thanks to the validation of a new 6-inch wafer bonder and to the development of a fully automated activation and characterization system, the fabrication of the first atomic vapour cells could start.

Parts procurement and building blocks manufacturing has also started for the miniature atomic clock (MAC) prototype. Tests and validation of the latter will then allow conducting the first assembly steps of the clock the physics package. The clock electronics is in about ready and clock control software programming has started. Integration of both the physics and the electronics should thus follow soon, depending on the access to the labs and the COVID-19 related parts delivery delays by the suppliers.

The high-density optically pumped magnetometer (OPM) activities are progressing. Preliminary prototype demonstrator designs are frozen so that parts manufacturing and components procurements could start for the different design variants. The availability of suitable low-power laser sources is a main concern for the OPM demonstrator. Different laser providers have been contacted in order to mitigate this risk. The low-density OPM activities are on a good way too. Prototypes were already fabricated and testing them is ongoing.

The first tasks related to the development of a compact atomic nuclear magnetic resonance gyroscope (NMRG) showed to be more time consuming than expected. The assessment of the gyroscope bandwidth is nevertheless finished and preliminary designs of the NMRG demonstrator could be defined. Dedicated compact glass-blown cells were also fabricated in order to refine the NMRG atomic vapour cell specifications thanks to a new test setup. Activities related to the preparation of the NMRG demonstrator testing and evaluation were anticipated in order to compensate for the delays encountered so far.

The GHz field imaging experiment using an atomic vapour cell is running. It is currently based on a glass blown cell and its performances are already two orders of magnitude better than those obtained with a former setup. The experiment will soon be upgraded with ultra-thin MEMS atomic vapour cells for improved spatial resolution. The breakthrough THz imaging experiment is also running well, and its optical path has been reduced by 65%. Further size shrinkage and performance enhancement of the experiment will be obtained by replacing the cubic cell by an ultra-thin MEMS atomic vapour cell with integrated reflectors.

Trace gas sensing schemes were experimented by using Rydberg excitation in a mixture of rubidium (idealized model system) and nitrogen. Promising sensitivities of 10ppb at an absolute concentration of 1ppm seem feasible. First tests of a pulsed excitation scheme for the detection of nitric oxide (NO) were performed. The requested laser system nevertheless encountered multiple malfunction and the experiment in thus delayed.

Overall, the MACQSIMAL quantum sensor demonstrator developments are progressing well, and the first miniature system prototypes should be ready for testing and validation by the end of 2020.
In parallel to these five technical objectives, a theoretical understanding of the different sensor’s limitations and of quantum enhancement strategies was realized.
The macQsimal consortium gathers world-leading academic groups in the field of quantum sensing and metrology who collaborate with research and technology organizations and industrial partners, thus contributing to expand EU leadership and excellence in hot atomic vapor based quantum technologies in view of forming the basis for future technologies.

By combining state-of-the-art sensor physics with the MEMS atomic vapour cell platform, MACQSIMAL will be able to deliver highly advanced prototypes and demonstrators. Hence the project is creating a strong link between fundamental and applied research, both being at the edge of the present understanding of theoretical concepts and of technical possibilities. Advanced squeezing, entanglement and cavity-QED methods will be applied for the first time in miniaturized sensors, bringing quantum enhancement closer than ever to industrial application.

This advanced, multi-target, quantum-enabled sensor platform will mark the start of a dynamic and multi-sector quantum sensor industry in Europe.

By developing high TRL quantum sensors prototypes, MACQSIMAL will allow quantum technologies to be adopted by the society in a near future. Indeed, a sensor like the optically pumped magnetometer (OPM) will allow the wide spreading of magnetoencephalographic (MEG) imaging systems for the diagnostic of brain related diseases thanks to the lower costs and the lower maintenance needs. Another sensor, the atomic gyroscope, should allow the future autonomous vehicles for more security thanks to their higher performances. Finally, miniature atomic clocks will allow future networks for a better synchronization and thus better performances.
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