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Historic breakthrough: Researchers inch closer to a clock that could replace GPS

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GPS is known for its reliability, accuracy, and accessibility even in the most remote areas. Off late there no alternatives to GPS that could parallel its accuracy and range have been conceived. But what if we say that very soon a real alternative to GPS could emerge that will drastically reduce our dependence on satellite mapping as the silver bullet solution?

Scientists in the Emergent Photonics Lab (EPic Lab) at the University of Sussex have undertaken pioneering research to a crucial element of an atomic clock with the help of cutting-edge laser beam technology. Atomic clocks have the potential to become a formidable alternative to GPS and provide users with enhanced functionality.

Improved efficiency

The latest development improves the efficiency of the lancet – which in a traditional clock is responsible for counting – by over 80%. This is a phenomenal feat given that scientists globally were striving hard to achieve it for years.

Published in the journal, Nature, the research paper is titled ‘Laser cavity-soliton microcombs’.

The UK mainly depends on the US and the EU for the satellite mapping that has its applications in literally everything, from the most quotidian of tasks to highly specialized activities that require precision. The downside of this arrangement is that it is not immune to political disturbances or volatility in the geopolitical or global economic scenario.

Dr Alessia Pasquazi from the EPic Lab in the School of Mathematical and Physical Sciences at the University of Sussex says “With a portable atomic clock, an ambulance, for example, will be able to access their mapping whilst in a tunnel, and a commuter will be able to plan their route whilst on the underground or without mobile phone signal in the countryside. Portable atomic clocks would work on an extremely accurate form of geo-mapping, enabling access to your location and planned a route without the need for satellite signal.”

She further adds that the breakthrough improves the efficiency of the part of the clock responsible for counting by 80%. This takes us one step closer to the realization of portable atomic clocks completely replacing satellite mapping within 20 years.

Optical atomic clocks are the apogee of time measuring devices. To put its unmatched precision in perspective, the probability of losing less than one second is in ten billion years in an atomic clock. However, atomic clocks are unwieldy due to massive weigh and this is one serious limitation that makes it almost impossible for an ordinary person to utilize it. We need something akin to miniaturization in the size of atomic clocks so that they could become handy and easy-to-use.

Technology at work

In an optical atomic clock, the reference, which is the pendulum in a conventional clock, is directly derived by the quantum property of a single atom confined in a chamber: it is the electromagnetic field of a light beam oscillating hundreds of trillions of times per second. The clock counting element required to work at this speed is an optical frequency comb – a highly specialized laser emitting, many precise colors.

Micro-combs diminish the frequency dimension with the help of tiny devices called microresonators and then enthrall the imagination of the global community over the past decade. Though one major shortcoming is that they are do not fulfill the requirements of

“Solitons are special waves that are particularly robust to perturbation. Tsunamis, for instance, are water solitons. They can travel unperturbed for incredible distances; after the Japan earthquake in 2011 some of them even reached as far as the coast of California”, says Dr Pasquazi.

“Instead of using water, in our experiments performed 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 on optical fibers, the same used to deliver internet in our homes.

“The soliton that travels in this combination has the benefit of fully exploiting the micro-cavities’ capabilities of generating many colors, whilst also offering the robustness and versatility of control of pulsed lasers. The next step is to transfer this chip-based technology to fibre technology – something that we’re exceptionally well-placed at the University of Sussex to achieve.”

Professor Marco Peccianti from the University of Sussex EPic Labs says, “We are moving towards the integration of our device with that of the ultra-compact atomic reference (or pendulum) developed by Professor Matthias Keller’s research group here at the University of Sussex. Working 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’re extremely excited by our plans, which range from partnerships with the UK aerospace industry – which could come to fruition within five years –  through to portable atomic clocks that could be housed in your phone and within driverless cars and drones within 20 years.”