法国MUQUANS的主要的技术是从Institut d'Optique和巴黎天文台（Observatoire de Paris OPTIQU）分离出来，已经有超过15年的积累。其主要的核心团队成员是量子绝对重力测量和原子钟领域的顶级人才。
Our products are based on a fully quantum approach resulting from 15 years of world-class scientific research conducted by our academic partners:
• LP2N, UMR 5298 CNRS – Institut d’Optique – Université de Bordeaux
• SYRTE, UMR 8630 CNRS – Observatoire de Paris – Université Pierre et Marie Curie
A global technology transfer agreement was signed between µQuanS and CNRS/Institut d’Optique/Observatoire de Paris. It allows µQuanS to fully exploit the technologies developed at SYRTE and LP2N. In particular, µQuanS was granted an exclusive operating licence of an international patent covering the core architecture of our gravimeter.
Our products are based on a really disruptive technology, relying on quantum manipulation of laser-cooled atoms. The general idea consists in trapping and cooling an ensemble of rubidium atoms thanks to a combination of laser beams and magnetic fields. This magneto-optical trap allows to trap several hundreds of million atoms in a cloud of a few mm diameter, and cool them down to a few microKelvins, just above the absolute zero!
This cloud of cold atoms is the raw material µQuanS is using to perform high precision measurements.
Starting from this, various quantum manipulation schemes can be applied, which offer the possibility to characterize different kinds of physical parameters with an extreme accuracy.
In particular, these techniques have proven to be extremely relevant for high precision time and inertial (acceleration/rotation) measurements.
Absolute Quantum Gravimeter
The Muquans Absolute Quantum Gravimeter is the first commercial gravimeter based on laser-cooled atoms. After 15 years of research, this technology has proven its capability to perform absolute gravity measurements at the microGal level over long periods of time.
• Compact and transportable sensor.
• Significantly low maintenance constraints (in particular, no moving parts in our vacuum chamber).
• Ease and quickness of Operation : the AQG is ready to measure within 1h (no laser alignment nor mechanical assembling,
no preliminary pumping, no superspring). User-friendly software requiring no knowledge in quantum physics.
• Absolute gravity measurement at the µGal level at a few Hz cycling frequency.
• Excellent immunity to ground vibrations thanks to an active compensation system (no mechanical isolation).
• Automated Continuous Data Acquisition for several months. No observed long-term drift.
• Station to station reproducibility of the absolute measurement within a few μGal.
With a single unit of the AQG one can now perform:
- station based long-term monitoring of g in presence of seismic noise
- local absolute determination of g and easy change of location
- gravity mapping without redundant loops and high-precision transfers of g (indoor mapping, gravity gradients …).
With the AQG, a station can be measured at the microGal level within 1h30 (set-up and calibration of the sensor included).
Principle of operation
The AQG relies on the same basic principle as absolute free fall gravimeters. However, instead of using a falling mirror, the gravity measurement is performed with falling laser-cooled atoms. This technique is one of the ballistic freefall method proclaimed by the BIPM (Bureau International des Poids et Mesures) as an official primary method for the measurement of gravity.
A typical measurement sequence is organized as follows:
• First, atoms are trapped in the vacuum chamber with lasers and cooled down to a temperature of a few µK.
• All laser beams are shut down so that the cold atoms experience a free-fall.
• The vertical acceleration experienced by the atoms during a 10 cm fall is precisely characterized with an advanced interferometric scheme relying on lasers.
This technique provides a very accurate gravity measurement method, which gives a direct access to the absolute value of the gravity. The AQG is therefore inherently calibrated and does not experience any measurable drift over time.
In addition, utilization of atom cooling and trapping techniques allows a fast measurement cycle, with a repetition frequency up to
5 Hz, and does not require any moving parts in the vacuum chamber, which leads to a very high reliability.
Here are the specification of our AQG:
|Sensitivity||50 µGal/√Hz (demonstrated)|
|Measurement frequency||2 Hz|
|Long-term stability||~ 1 μGal|
|Accuracy||A few μGal (under evaluation)|
The characteristics of the physics package of the AQG are:
|Dimensions||Sensor head: h = 70 cm / D = 38 cm|
Laser & electronics: 100 x 50 x 70 cm3
|Mass||100 kg (without flight cases)|
|Power consumption||300 W typical|
A hybridized version of our AQG is also available. It allows to obtain an acceleration signal which is:
• Very large band [DC ; 430 Hz], and ultra-sensitive
• Accurate and ultra-stable on the long-term.
This product is the first and only commercially available atomic clock based on ultra-cold atoms in the world. This unique solution is the result of more than 15 years of experience acquired by our academic partner, LNE-SYRTE, one of the major international experts in the field of time standards.
The approach developed by Muquans relies on laser manipulation of cold atoms. We are able to produce more than 10 times per second a dense atomic cloud showing an exceptional stability over time, quasi-independently of external conditions. This unique atomic medium allows us to perform spectroscopy measurements with an exceptionally high signal-to-noise ratio, over extremely long periods of time.Therefore, this approach enables the MuClock to offer exceptional performances in terms of both short and long-term stability, as well as accuracy.
Principle of operation
The basic principle of the MuClock is very similar to the one utilized in the atomic fountains for the definition of the Atomic International Time. However, instead of launching a cloud of cold atoms through a microwave cavity where the atoms are interrogated, the preparation of the cold atomic sample is done inside the microwave cavity. This preparation phase is thus quickly followed by the interrogation of the atoms, which allows to perform measurements with a high repetition frequency, higher than 10 Hz. With this approach, we therefore obtain performances close to atomic fountains with a very significant weight reduction and increase in compacity.
A typical measurement sequence is organized as follows:
• First, atoms are cooled in the vacuum chamber with lasers down to a temperature of a few µK.
• All laser beams are shut down, then the atoms undergo Ramsey interrogation in the microwave cavity.
• Characterization of the clock transition signal through a laser absorption measurement. This signal allows us to precisely determine the clock frequency, which for rubidium atoms is close to 6.834 682 612 Ghz. This atomic signal is used to lock the local oscillator of the MuClock in order to guarantee its long-term stability and accuracy.
|1 s||2.2 10-13|
|10 s||7.0 10-14|
|100 s ||2.0 10-14|
|1 000 s ||7.0 10-15|
|Floor||< 4.0 10-15 (@ 5 000 s)|
|Offset (Hz)||5MHz Output|
|10||-140 dBc |
|1,000 ||-155 dBc|
High predictability: low floor noise and accuracy of a few 10-15 expected2
Output frequencies: 5, 10 and 100 MHz
Synchronization options: PPS input & output
|Operating power||200 W|
|Peak power||250 W|
|Width ||51 cm|
|Depth ||40 cm|
1. Esnault et al, Proceedings of the IEEE International Frequency Control Symposium, 381-385 (2008)
2. Esnault et al, Advances in Space Research 47, 854-858 (2011)
• Time metrology and calibration
• Global Navigation Satellite Systems & radionavigation
Laser systems and laser optics
Based on its deep expertise in high-precision quantum measurements with cold atoms, Muquans provides turnkey high-performance laser solutions. These solutions were carefully qualified to offer scientists strong robustness and reliability, that will guarantee a day-to-day nominal operation of their experimental setup on the long-term, and will alleviate them from the technological complexity of usual optical set-ups.
The performances of these solutions have been validated on our cold-atom gravimeter and atomic clock.
Frequency-controlled laser systems
These laser systems offer fast tunability and accurate control of the absolute laser frequency. Tailored solutions with several fiber outputs can be proposed to develop a design adapted to any experimental setup. Such laser systems constitute a turnkey, reliable, and easy to use solution to implement immediate and ultra-stable atom cooling, atom interferometry, or Bose-Einstein Condensation.Download our datasheet
High-power frequency-stabilized laser system
This solution offers a cost-effective and flexible solution for various experimental setups. It can generate up to 1 W output power and features a robust and highly reliable frequency stabilization which results in remarkable spectral characteristics.Download our datasheet
|High-power high-efficiency frequency-doubling module|
This compact module allows for the generation of several watts of optical power in the visible range of the spectrum with a remarkable wall-plug efficiency, and excellent optical performances.Download our datasheet
|Ultra-stable fibered beam splitters/combiners|
This line of products offers high-performance, robust, and ultra-stable power splitting with an adjustable ratio in a fully integrated package.Download our datasheet