This is an optical lattice clock, which uses neutral atoms of strontium, which are held in a vacuum chamber where they are confined in an optical lattice, which is a periodic array of laser light.
Optical lattices are used because they allow the aggregation of signals from thousands of atoms, increasing the signal-to-noise ratio in comparison with using one ion or a few ions in a ion trap. In comparison with a solid crystal holding the same atoms as an optical lattice, the distance between atoms is much higher in the optical lattice, which avoids the interactions between neighbor atoms that would widen the resonance peaks in the spectra of the atoms.
This announcement is indeed extremely important. Optical lattice clocks are much more precise than the old microwave atomic clocks that use cesium, rubidium or hydrogen masers.
Cesium clocks, rubidium clocks and hydrogen masers have been available commercially for many decades, and the first two exist in miniaturized form, which you can mount on a PCB, like you can do with quartz clocks.
On the other hand, optical clocks, which use either optical lattices or ion traps, and which also use multiple lasers and a lot of high-precision optical devices, where made until now only individually, in the laboratories of various research institutions (like NIST, which might be affected by down-scaling now), and they are typically very big. Only a few are so small as to be transportable by a vehicle.
Nov this announcement is for the first optical lattice clock that is mass produced and available commercially. It is said that it is also small enough to be transportable.
This will greatly extend the applications of optical clocks, because until now very few had the resources and competence to build one. From now on, there will be the alternative to just buy it and use it.
Moreover, this makes much closer the moment when the base of the entire international system of units, the definition of the second as implemented by a cesium clock, will be replaced by a definition of the second based on an optical clock, perhaps in 2030.
For now, the main problem in the redefinition of the second is that there is not a single type of optical clock, but there are many optical clocks that are much more precise than cesium clocks, and they use atoms or ions of various chemical elements, e.g. calcium, strontium, ytterbium, aluminum, lutetium, mercury and a few others.
It is not clear which of these optical clocks will be the best, even if for now, as demonstrated by this announcement, strontium-based clocks appear to use the most mature technology.
For this reason, it is possible that the future definition of the second will no longer use a single atomic clock, but it will define the second based on a geometric mean, possibly weighted, of the periods of several distinct kinds of optical atomic clocks.
"Miniaturized", means for now a one-meter-high rack weighing 200 kilograms.
However, this is really impressive miniaturization over most previous optical clocks, which typically fill a big room.
The price is 3.3 million dollars, which is also cheap in comparison with the previous costs for developing and building an optical clock.
While in the past Hewlett-Packard has been the first and for much time the main commercial provider of atomic clocks, it appears that this task has been now relayed to Japan's Shimadzu.
Which is seems to be about 1/5th the size, 1/10th the cost, and maybe 1/100th the long term stability (though the optical lattice clock doesn't have an adev chart, so I'm just comparing 10^-15 with 10^-18).
I wonder if the lattice clock can be moved while operating? IIRC the CRB can't, and requires better than 1 degree leveling so the cooled rb cloud can be in freefall.
The automatic translation is bad.
This is an optical lattice clock, which uses neutral atoms of strontium, which are held in a vacuum chamber where they are confined in an optical lattice, which is a periodic array of laser light.
https://en.wikipedia.org/wiki/Optical_lattice_clock
Optical lattices are used because they allow the aggregation of signals from thousands of atoms, increasing the signal-to-noise ratio in comparison with using one ion or a few ions in a ion trap. In comparison with a solid crystal holding the same atoms as an optical lattice, the distance between atoms is much higher in the optical lattice, which avoids the interactions between neighbor atoms that would widen the resonance peaks in the spectra of the atoms.
This announcement is indeed extremely important. Optical lattice clocks are much more precise than the old microwave atomic clocks that use cesium, rubidium or hydrogen masers.
Cesium clocks, rubidium clocks and hydrogen masers have been available commercially for many decades, and the first two exist in miniaturized form, which you can mount on a PCB, like you can do with quartz clocks.
On the other hand, optical clocks, which use either optical lattices or ion traps, and which also use multiple lasers and a lot of high-precision optical devices, where made until now only individually, in the laboratories of various research institutions (like NIST, which might be affected by down-scaling now), and they are typically very big. Only a few are so small as to be transportable by a vehicle.
Nov this announcement is for the first optical lattice clock that is mass produced and available commercially. It is said that it is also small enough to be transportable.
This will greatly extend the applications of optical clocks, because until now very few had the resources and competence to build one. From now on, there will be the alternative to just buy it and use it.
Moreover, this makes much closer the moment when the base of the entire international system of units, the definition of the second as implemented by a cesium clock, will be replaced by a definition of the second based on an optical clock, perhaps in 2030.
For now, the main problem in the redefinition of the second is that there is not a single type of optical clock, but there are many optical clocks that are much more precise than cesium clocks, and they use atoms or ions of various chemical elements, e.g. calcium, strontium, ytterbium, aluminum, lutetium, mercury and a few others.
It is not clear which of these optical clocks will be the best, even if for now, as demonstrated by this announcement, strontium-based clocks appear to use the most mature technology.
For this reason, it is possible that the future definition of the second will no longer use a single atomic clock, but it will define the second based on a geometric mean, possibly weighted, of the periods of several distinct kinds of optical atomic clocks.
EDIT:
Some announcements about this in English:
https://www3.nhk.or.jp/nhkworld/en/news/20250305_33/
https://english.kyodonews.net/news/2025/03/c0945eb14bb6-japa...
https://www.bloomberg.com/news/articles/2025-03-05/world-s-m...
"Miniaturized", means for now a one-meter-high rack weighing 200 kilograms.
However, this is really impressive miniaturization over most previous optical clocks, which typically fill a big room.
The price is 3.3 million dollars, which is also cheap in comparison with the previous costs for developing and building an optical clock.
While in the past Hewlett-Packard has been the first and for much time the main commercial provider of atomic clocks, it appears that this task has been now relayed to Japan's Shimadzu.
I wonder what a feature by feature comparison would look like with the commercial cold rb optical clock?
https://spectradynamics.com/products/crb-clock/
Which is seems to be about 1/5th the size, 1/10th the cost, and maybe 1/100th the long term stability (though the optical lattice clock doesn't have an adev chart, so I'm just comparing 10^-15 with 10^-18).
I wonder if the lattice clock can be moved while operating? IIRC the CRB can't, and requires better than 1 degree leveling so the cooled rb cloud can be in freefall.