LESSO: Laser etero-integrato a stato solido per trappole ottiche

Atomic clocks are sophisticate instruments used for extremely precise measurements of time.  While a high quality wristwatch measures the time with an accuracy of about 5 seconds per year ultraprecise atomic clocks (strontium clock NIST 2015) measure the time with an accuracy of 1 second in 15 billions of years. In modern measurement systems used in metrology, measuring the time with high accuracy, allows also to measure the position with accuracy. For these reason atomic clocks find application as reference  in navigation and position systems like GPS.

One of the critical components of an optical atomic clock are high performance lasers. The emitted light of such lasers has to be “ultra-pure” in colour and extremely stable over time. In the core of the atomic clock the emission of these lasers is then used to analyse and to manipulate atomic transitions of single isolated cold atoms – in our specific case the atom strontium.

Today a relatively compact optical atomic clock has a volume of about 2 m3. Especially for space missions much more compact optical atom clock will represent an enormous advantage.  The project consortium - formed by the Bruno Kessler Foundation, the Department of Physics of the University of Pisa, the Physics Department of the University of Trento and Atomsensor SRL - aims on the radical miniaturisation of one of the components of the atomic clock, namely the laser source used to manipulate the strontium atoms. The key to the miniaturisation is the integration of laser-crystals, grown by the Physics Department of Pisa, with tiny optical circuits realised with silicon microfabrication technology (the same technology allowed the radical miniaturisation of components nowadays used in computers, smartphones, and consumer electronics etc.). The core of the laser will have a volume of some tens of cubic centimetres and its performance will be tested at the atomic clock of Atomsensor SRL in Florence, Italy.