World's first commercial optical lattice clock with an error of 1 second in 10 billion years: Shimadzu introduces next-generation time measurement technology in a miniaturized form

On March 5, Shimadzu Corporation launched the "Aether clock OC 020," a strontium-based optical lattice clock with an accuracy of 18 digits and began accepting orders. Notably, the suggested sales price (including tax) is 500 million yen, which varies depending on the system configuration. The sales target is 10 units over three years in the domestic and overseas markets.

An optical lattice clock is a type of atomic clock that achieves more than 100 times the accuracy of cesium atomic clocks, which are used for the current standard definition of a second. An accuracy of 18 digits is extremely high, equivalent to an error of 1 second per 10 billion years. Optical lattice clocks are attracting attention as leading candidates for the next-generation definition of a "second."

The latest product is a device that was successfully miniaturized to a volume of 250 L in November last year. It is the world's first commercially available optical lattice clock. It can be used as a time standard in standard organizations, universities, research institutes, etc. as well as in various other fields for different purposes.

The company began joint research on optical lattice clocks in 2017 with a group led by Professor Hidetoshi Katori of the Department of Applied Physics, Graduate School of Engineering at the University of Tokyo. They developed a control system for such clocks in an experiment to verify the general theory of relativity at Tokyo Skytree in the following year. Subsequently, the company worked on the development of on-board lasers and products. In addition to achieving miniaturization, it improved the robustness of lasers and developed a technology to automatically adjust and control the laser frequency, which resulted in the world's first commercialized product.

Conventional optical lattice clocks require frequent and complicated adjustments, but this product can substantially reduce the burden on workers. Because the clock is compact and easy to relocate, it can be used to measure gravitational potential using general relativity in various fields. Optical lattice clocks have the potential to become a future social infrastructure. For example, they can be used for monitoring plate movement with an accuracy of several centimeters, monitoring vertical crustal movements due to volcanic activities, precisely observing crustal movements (elevation changes) that occur over several hours to several years, and establishing ultrahigh-precision elevation difference measurement and positioning systems.

This research has been conducted since 2018 with support from the JST Future Society Creation Program "Space-time information platform with a cloud of optical lattice clocks."

■ The first optical lattice clock was invented in 2001 by Hidetoshi Katori, who was an assistant professor at the University of Tokyo at the time. Atoms are captured one by one in a container (optical lattice) created by laser light of a special wavelength known as the "magic wavelength," and the atomic vibrational frequencies are precisely measured without any interaction between the atoms. The entire optical lattice can capture numerous atoms, and by measuring all the atomic vibrational frequencies at once and taking the average, high accuracy can be achieved in a short time.