Scientists are approaching a clock that could replace GPS and Galileo

Scientists at the EPENT Laboratory (Emergent Photonics Lab) of the University of Sussex have come up with a crucial element of the atomic clock, namely devices likely to reduce our future dependence on satellite mapping, thanks to an advanced laser beam technology. Their development greatly enhances the effectiveness of the lancet (which, in a traditional clock, is responsible for counting), by 80% – a goal sought by scientists around the world.

At present, the United Kingdom depends on the United States and the EU for satellite mapping that many of us have on our phones and in our cars. This makes us vulnerable not only to the whims of international politics, but also to the availability of the satellite signal.

Dr. Alessia Pasquazi of the EPic Laboratory of the School of Physical and Mathematical Sciences at the University of Sussex explains the breakthrough: "With a portable atomic clock, an ambulance, for example, will still have access to its mapping in a tunnel., and commuters will be able to plan their route by subway or without mobile phone signal to the countryside.The portable atomic clocks would operate on a form of geo-mapping extremely accurate, allowing unrestricted access to your position and your route to the satellite signal.

"Our breakthrough improves efficiency by 80% of the part of the clock responsible for counting. This brings us even closer to the idea that portable atomic clocks are replacing satellite mapping, such as GPS. , which could happen in 20 years.This technology will change every day people live as well as potentially applicable in driverless cars, drones and the aerospace industry.it's exciting that this development has taken place here in Sussex. "

Optical atomic clocks are at the top of time measuring devices, losing less than a second every ten billion years. Curiously, they are massive devices, weighing hundreds of kilograms. To have an optimal practical function that can be used by an average person, it is necessary to reduce their size considerably while keeping the precision and the speed of the clocks on a large scale.

In an optical atomic clock, the reference (the pendulum of a traditional clock) is directly derived from the quantum property of a single atom confined in a chamber: it is the electromagnetic field of a clock. a light beam oscillating several hundreds of billions of times per second. The clock counting element needed to work at this speed is an optical frequency comb, a highly specialized laser emitting simultaneously many precise colors, spaced equally in frequency.

Micro-combs reduce the size of frequency combs by exploiting tiny devices called optical microresonators. These devices have captivated the imagination of the scientific community worldwide over the past decade, promising to realize the full potential of frequency combs in a compact form. However, these are delicate, complex devices to use and that do not generally meet the requirement of practical atomic clocks.

The breakthrough at the EPic laboratory, detailed in an article published today (Monday, March 11) in the newspaper, Photonic Nature, is the demonstration of an exceptionally efficient and robust micro-comb based on a single wave type called "laser cavity soliton".

"Solitons are special waves that are particularly resistant to disturbances, for example, tsunamis are water solitons, they can travel incredible distances, and after the earthquake in Japan, some have even reached the coast. . " of California.

"Instead of using water, in our experiments conducted by Dr. Hualong Bao, we use pulses of light, confined in a tiny cavity on a chip.Our distinctive approach is to insert the chip in a laser based optical fibers, the same deliver internet to us.

"The soliton that travels in this combination has the advantage of fully exploiting the capabilities of micro-cavities to generate many colors, while still offering the robustness and versatility of pulsed laser control." The next step is to transfer this chip-based technology to fiber optic technology – a goal for which we are exceptionally well placed at the University of Sussex. "

Professor Marco Peccianti of the EPic lab at the University of Sussex adds: "We are moving towards the integration of our device with that of the ultra-compact atomic reference (or pendulum) developed by the research group of Professor Matthias Keller, Here at the University of Sussex Together, we plan to develop a portable atomic clock that could revolutionize the way we count time in the future.

"Our development represents a significant step forward in the production of practical atomic clocks and we are extremely excited about our projects, which range from partnerships with the British aerospace industry, which could materialize in five years, to atomic clocks. laptops that could be housed in your phone and in driverless cars and drones within 20 years. "

Explore further:
Quantum optical micro-combs

More information:
Microcombs with laser-soliton cavity, Photonic Nature (2019). DOI: 10.1038 / s41566-019-0379-5, https://www.nature.com/articles/s41566-019-0379-5