Periodic Reporting for period 2 - macQsimal (Miniature Atomic vapor-Cells Quantum devices for SensIng and Metrology AppLications)
Berichtszeitraum: 2020-04-01 bis 2022-07-31
Sensors provide the interface between the real world and the digital world. Quantum technologies are poised to revolutionize this interface, in particular for sensor-driven industries such as navigation, telecommunication, transportation, as well as medical imaging and diagnostics.
macQsimal developed quantum-enabled sensors with outstanding sensitivity for five key physical observables: magnetic fields, time, rotation, electro-magnetic radiation and gas concentration. The sensors were chosen for their high impact and their potentially reduced time to market. Within macQsimal, all sensors reached as expected technology readiness levels (TRLs) between 3 and 6. Depending on their respective TRLs, the sensor prototypes will follow their own exploitation strategies. Some will start an industrialisation process, while others will need some additional development steps before reaching the market.
In macQsimal, the common core technology for all sensors was atomic vapor cells, realized as integrated microelectromechanical systems (MEMS) at the wafer-level. Fabricating such atomic vapor cells as MEMS will allow for high-volume, high-reliability and low-cost deployment of miniaturized, integrated sensors, critical to their wide-spread adoption.
macQsimal has thus combined state-of-the-art sensor physics with the MEMS atomic vapor cell platform to develop advanced prototypes and demonstrators, and has thus contributed to kick-starting a competitive European quantum sensor industry.
macQsimal developed quantum-enabled sensors with outstanding sensitivity for five key physical observables: magnetic fields, time, rotation, electro-magnetic radiation and gas concentration. The sensors were chosen for their high impact and their potentially reduced time to market. Within macQsimal, all sensors reached as expected technology readiness levels (TRLs) between 3 and 6. Depending on their respective TRLs, the sensor prototypes will follow their own exploitation strategies. Some will start an industrialisation process, while others will need some additional development steps before reaching the market.
In macQsimal, the common core technology for all sensors was atomic vapor cells, realized as integrated microelectromechanical systems (MEMS) at the wafer-level. Fabricating such atomic vapor cells as MEMS will allow for high-volume, high-reliability and low-cost deployment of miniaturized, integrated sensors, critical to their wide-spread adoption.
macQsimal has thus combined state-of-the-art sensor physics with the MEMS atomic vapor cell platform to develop advanced prototypes and demonstrators, and has thus contributed to kick-starting a competitive European quantum sensor industry.
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 applications targeted in the project, including a check for the freedom to operate (FTO). The specifications for the different sensor prototypes and their essential building blocks were then defined and validated. The first technical tasks were dedicated to the atomic vapor cell designs and the corresponding quantum sensor prototype designs, considering the existing patents and the respective FTO.
The atomic vapor cell fabrication could start early in the project thanks to the validation of a new 6-inch wafer bonder at CSEM and to the development of a fully automated activation and characterization system. The first atomic vapor cells produced in macQsimal were for the miniature atomic clock, for which the design and the technological readiness level (TRL) was the most advanced at the beginning of the project. Vapor cells for the other applications were fabricated all along the project duration. Some redesign and additional fabrication runs were realized to correct for evidenced limitations or to allow for better performances and additional features.
The project objectives were reached thanks to an excellent teamwork, overcoming even the barriers imposed by the COVID-19 pandemic. A project extension of 10 months was nevertheless requested to allow finalizing the tremendous work foreseen in macQsimal, the result of which is summarized below in the form of a list of achievements:
The following prototypes and demonstrators were developed:
- Compact, high temperature, high-density optically-pumped magnetometer (OPM) prototype (based on MEMS atomic vapor cells) working in the spin exchange relaxation-free (SERF) regime. TRL 3 -> 4.
- Compact room-temperature low-density OPM prototype (based on specifically coated millimetre-sized glass atomic vapor cells). TRL 4 -> 6.
- Miniature atomic clock (MAC) pre-industrial prototype, including the physics package (PP), the electronic circuit board (EP) and the magnetic shielding. A low power electronic circuit articulated around an application specific integrated circuit (ASIC) was benchmarked with the EP. TRL 4 -> 6.
- Tabletop clock demonstrator based on a microfabricated Rb vapour cell and a miniature microwave resonator for pulsed interrogation based on Ramsey scheme. TRL 3 -> 4.
- Compact NMR-gyroscope (NMRG) demonstrator composed of the representative building blocks: MEMS atomic vapor cell, pump/probe laser sources, optics, magnetic shielding and coils. TRL 3 -> 4.
- Laboratory setup for imaging of microwave (GHz) fields using MEMS vapor cells, with frequency-tunability in the few GHz to tens of GHz range and sub-millimetre spatial resolution. The setup was also operated as a microwave analyser. TRL 2 -> 4.
- Laboratory experimental setup operated as a GHz field sensor for direct detection of microwave magnetic fields at GHz frequency.
- Laboratory setup for imaging of THz beams with frequencies in the THz gap range using standard optical cuvettes and MEMS cells, by detecting the E-field component with Rydberg atoms. The setup dimension could be reduced by 65%, proving that a low SWaP demonstrator is viable.
- Laboratory experiments in through flow cells with integrated electronics for Rydberg-based gas sensing of Rubidium and nitric oxide (NO), and their calibration at ppm/sqrt(Hz) levels.
The following quantum-enhancement strategies were conducted:
- Development of cavity-QED, spin squeezing, and optical squeezing methods for vapor-phase atomic sensors.
- Exploiting entanglement and spin squeezing in magnetometry: an improvement of ~10 % compared to the projection noise level.
- Theoretical study for quantum-enhancement strategies for NMR gyroscopes.
- Theoretical study for quantum-enhancement strategies for GHz field sensing with vapor cells.
In conclusion, the macQsimal consortium has reached most of its challenging objectives, both in terms of TRL increase and reduced time-to-market, and quantum-enhancement strategies for future high-performing novel quantum sensors.
The atomic vapor cell fabrication could start early in the project thanks to the validation of a new 6-inch wafer bonder at CSEM and to the development of a fully automated activation and characterization system. The first atomic vapor cells produced in macQsimal were for the miniature atomic clock, for which the design and the technological readiness level (TRL) was the most advanced at the beginning of the project. Vapor cells for the other applications were fabricated all along the project duration. Some redesign and additional fabrication runs were realized to correct for evidenced limitations or to allow for better performances and additional features.
The project objectives were reached thanks to an excellent teamwork, overcoming even the barriers imposed by the COVID-19 pandemic. A project extension of 10 months was nevertheless requested to allow finalizing the tremendous work foreseen in macQsimal, the result of which is summarized below in the form of a list of achievements:
The following prototypes and demonstrators were developed:
- Compact, high temperature, high-density optically-pumped magnetometer (OPM) prototype (based on MEMS atomic vapor cells) working in the spin exchange relaxation-free (SERF) regime. TRL 3 -> 4.
- Compact room-temperature low-density OPM prototype (based on specifically coated millimetre-sized glass atomic vapor cells). TRL 4 -> 6.
- Miniature atomic clock (MAC) pre-industrial prototype, including the physics package (PP), the electronic circuit board (EP) and the magnetic shielding. A low power electronic circuit articulated around an application specific integrated circuit (ASIC) was benchmarked with the EP. TRL 4 -> 6.
- Tabletop clock demonstrator based on a microfabricated Rb vapour cell and a miniature microwave resonator for pulsed interrogation based on Ramsey scheme. TRL 3 -> 4.
- Compact NMR-gyroscope (NMRG) demonstrator composed of the representative building blocks: MEMS atomic vapor cell, pump/probe laser sources, optics, magnetic shielding and coils. TRL 3 -> 4.
- Laboratory setup for imaging of microwave (GHz) fields using MEMS vapor cells, with frequency-tunability in the few GHz to tens of GHz range and sub-millimetre spatial resolution. The setup was also operated as a microwave analyser. TRL 2 -> 4.
- Laboratory experimental setup operated as a GHz field sensor for direct detection of microwave magnetic fields at GHz frequency.
- Laboratory setup for imaging of THz beams with frequencies in the THz gap range using standard optical cuvettes and MEMS cells, by detecting the E-field component with Rydberg atoms. The setup dimension could be reduced by 65%, proving that a low SWaP demonstrator is viable.
- Laboratory experiments in through flow cells with integrated electronics for Rydberg-based gas sensing of Rubidium and nitric oxide (NO), and their calibration at ppm/sqrt(Hz) levels.
The following quantum-enhancement strategies were conducted:
- Development of cavity-QED, spin squeezing, and optical squeezing methods for vapor-phase atomic sensors.
- Exploiting entanglement and spin squeezing in magnetometry: an improvement of ~10 % compared to the projection noise level.
- Theoretical study for quantum-enhancement strategies for NMR gyroscopes.
- Theoretical study for quantum-enhancement strategies for GHz field sensing with vapor cells.
In conclusion, the macQsimal consortium has reached most of its challenging objectives, both in terms of TRL increase and reduced time-to-market, and quantum-enhancement strategies for future high-performing novel quantum sensors.
The macQsimal consortium gathered world-leading academic groups in the field of quantum sensing and metrology to collaborate with research and technology organizations and industrial partners, thus contributing to expanding EU leadership and excellence in hot atomic vapor-based quantum technologies.
By combining state-of-the-art sensor physics with the MEMS atomic vapor cell platform, macQsimal has delivered 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 have been applied for the first time in miniaturized sensors, bringing quantum enhancement closer than ever to industrial application.
By developing high TRL quantum sensors prototypes, macQsimal allows quantum technologies to be adopted by the society in a near future. Exploitation strategies have been elaborated in this respect, considering the achieved TRLs and Switzerland's exclusion from Horizon Europe funding.
As an example of societal impact, 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 (EU’s Vision Zero objective), thanks to their higher performances and reduced SWaP. Finally, the availability of European MACs with excellent performances will allow future networks for a better synchronization, as well as early-adopter to test and validate the use of such MAC in numerous new applications.
By combining state-of-the-art sensor physics with the MEMS atomic vapor cell platform, macQsimal has delivered 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 have been applied for the first time in miniaturized sensors, bringing quantum enhancement closer than ever to industrial application.
By developing high TRL quantum sensors prototypes, macQsimal allows quantum technologies to be adopted by the society in a near future. Exploitation strategies have been elaborated in this respect, considering the achieved TRLs and Switzerland's exclusion from Horizon Europe funding.
As an example of societal impact, 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 (EU’s Vision Zero objective), thanks to their higher performances and reduced SWaP. Finally, the availability of European MACs with excellent performances will allow future networks for a better synchronization, as well as early-adopter to test and validate the use of such MAC in numerous new applications.