Atomic-optical magnetometer has been one of the leading areas in quantum technology. In this type of magnetometer information about the magnetic field is mapped to the atomic spin state, which is prepared and monitored by light.

The main interest of our group is to exploit quantum resources such as squeezing and entanglement in order to enhance the capacity, sensitivity and speed in atomic-optical magnetometers. We aim at developing new methodological approaches and implement robust experimental procedures at the quantum interface between light and warm atomic ensembles in order to perform sensing at the ultimate limits of precision. We are also interested in practical applications of ultra-sensitive magnetometer, for instance in biomedicine or in security screening. 

Currently, we are exploring two reseach directions:

• Spin noise spectroscopy in high density alkali atomic ensembles:  Spin-noise spectroscopy contains useful information about the spin system, allowing for the study of atomic properties without externally perturbing the system. We use Faraday rotation of off-resonant light to passively detect the spin noise in an equilibrium ensemble of room-temperature paramagnetic alkali atoms experiencing a DC magnetic field. In the regime of high alkali density and low magnetical field, strong correlations between the hyperfine levels result in previously unnoticed features in the spin noise spectrum. 
• Simultaneous reduction of all quantum noises in an atomic-optical magnetometer: In an atomic-optical magnetometer information about the magnetic field is mapped to the atomic spin state, which is then monitored by light. These magnetometers have reached a level of sensitivity limited by quantum effects. We can identify three noise sources originating from the quantum nature of light and atoms that could potentially limit the sensitivity of the magnetometer: photon shot noise, atom shot noise (also called spin projection noise) and the back-action noise. We aim to realize a magnetometer that will address for the first time all types of quantum noise that affect an atomic-optical magnetometer and demonstrate quantum advantage in the measurement. To this end, we will use stroboscopic modulation of the probe light synchronized with the atomic spin precession, resulting in atomic-spin squeezed and light-squeezed states.

Scientific space missions require an ever-increasing level of optical complexity. Beams must be split, recombined and coupled in and out of optical fibres. Modern optical platforms must include active elements such as acousto-optic and electro-optic modulators, as well as mechanical shutters. Example applications include the LISA interferometer, where optical laser beams must be prepared and controlled, or the STE-QUEST II and PHARAO atom-clock missions, where many different laser beams must be controlled in frequency and amplitude in order to cool and manipulate atomic clouds. The main challenge is that the beams must be coupled into single mode optical fibres after having traversed a number of active and passive optical elements. This can only be achieved using optical breadboard technology.

We are currently developing in colaboration with ESA novel technologies for beam steering on compact optical bread boards. The aim of the project is to simplify existing techniques whilst increasing stability and scalability.

The standard solution to reduce the effect of unavoidable thermal variations is to use a thick base-plate from an ultra-low-expansion (ULE) material such as Zerodur. One then mounts optical elements onto the base-plate using methods like Hydroxide-catalysis bonding (LISA) or UV-curable optical adhesives (MAIUS-QUANTUS). In many cases (like a beam-splitter to be glued) the vertical angle can only be adjusted by machining the optical element itself. Where precise adjustments or more complex shapes are required, currently one has to use non-ULE materials such as Invar or sapphire. The fibre couplers, for example, typically consist of in complex housings allowing both angle and position displacement. This often requires the use of non-ULE materials.

Current Projects

SkinUP:

The upgrade of the Skinakas Observatory for optical and quantum communication ground station, which is financed by the European Space Agency under the acronym SkinUP.

CARIOQA-PMP

CARIOQA aims to develop an Engineering Model (EM) of the mission’s instrument and to increase the Technology Readiness Level (TRL) of the critical subsystems up to 5. An EM is a light representative model in terms of form, fit and function used for the design qualification test program, it is not intended to flight. Complementary EU industrial partners develop the subsystems of the instrument (i.e. Physics Package, Laser System, Microwave Source and Ground Support Equipment) and increase its TRL by assessing the critical technologies in relevant environments. Excellent institutes bring their quantum expertise for the definition of the EM and the mastering of its performance. 

SpaceTools:

This project is developing novel space-compatible laser stabilisation tools, which are aimed at Rb-based atom quantum sensors