Safire

Progress in commercializing cold-atom-based quantum instruments is limited by the availability of reliable size, weight, power and cost-reduced narrow linewidth lasers. Great progress has been made in the development of semiconductor laser platforms to allow for many of the laser-cooling functions to be achieved, but some of the more-challenging functional requirements are unlikely to be met by this approach. The Safire project will accelerate the commercialisation of cold-atom Quantum technologies including optical clocks, gravimeters, inertial-navigation units and ion-trap quantum computers.

In optical clocks, the magic wavelengths for the creation of an optical lattice at 813 nm (Sr) and 759 nm (Yb) require high power and narrow linewidth. This function is generally achieved with a tunable Ti:Sapphire laser. These laser systems generally cost ~£100k and are large and fragile devices, making them one of the primary impediments to system miniaturisation and cost-reduction.

Many quantum instruments based upon cold-atom interferometry, such as gravimeters and inertial navigation units for GNSS-free navigation, require a narrow-linewidth Raman-beam to operate. In Rubidium interferometers the relatively high-power (multiple Watts in some systems) and narrow linewidths (~10s of kHz) required are often provided by a frequency-doubled telecoms-fibre laser. These lasers are expensive (\>£50k) and their complexity often leads to unreliable operation. This represents a significant risk to the potential commercialisation of interferometer-based instruments that must be fielded in non-laboratory environments.

The Safire project will develop a new capability in ultra-compact diode-pumped-solid-state lasers that addresses the requirements of the optical lattice function in clocks, the Raman-beam function in atom interferometers, and also for ion-trap quantum computers, in a form-factor appropriate for integration into robust Quantum instruments usable outside of the laboratory environment. This development builds upon NPL's long history in optical clock development, Optocap and RAL-Space's experience in micro-ECDLs for cold-Rubidium instruments from the Innovate REMOTE project, and on Caledonian Photonics' capability in miniaturised, robust monolithic DPSS lasers.