Duration: 36 months
Background & Motivation:
Gravity field mapping from space provides crucial information for the understanding of climate change, hydro/biosphere evolution, and tectonics and earthquake prediction. Atom-interferometric Quantum Sensors offer far superior long-term stability and higher sensitivity. Thus atom-quantum-sensors are considered by ESA as being part of a potential future instrument. ESA’s future geodesy mission will include quantum sensors as a candidate for the following mission. Similarly, the EU is planning a dedicated atom-interferometric EO-mission. Especially at ESA, there has been a large effort at ESA-EOP and TEC over the past 10 years developing quantum sensor and the related subsystems, the implementation of which has been accepted by the adoption of the MAGIC/NGGM as gravity mission at the last ESA ministerial. The following mission will include quantum sensor and this PhD is very well aligned with the timeframe.The Challenge Atom-quantum sensors rely on the probing and manipulation of atoms using lasers, which in turn must be stabilized and controlled with extreme precision and reliability. Lasers are stabilized using atomic references. Most earth-bound laser-stabilization systems rely on frequency modulation saturation spectroscopy. Since the lasers have to be free of any sidebands, this requires complex radiofrequency modulation using external electro- or acousto- optic modulators.
The Proposal
In this project, we will develop a novel spectroscopy for laser stabilization. It will be based on Zeeman modulating the atomic resonance as opposed to the laser itself. This eliminates the need for external laser-frequency modulation devices. We will address the crucial points of sensitivity to laser-intensity noise, temperature fluctuations and magnetic field sensitivity. Finally, we will apply the optical-beam steering techniques (OBST) recently-developed by us for ESA, in order to achieve maximal stability with minimal system-complexity.
