The optical control of quantum matter is a fast-growing research field at the interface between quantum optics and material science. In the Dynamic Quantum Materials Laboratory, we use ultrashort light pulses to drive materials out of equilibrium in order to generate novel functionalities. To this end, we generate picosecond (10-12 s) light pulses in the terahertz (THz) spectral range, where many collective excitations in matter are accessible. These intense pulses are driving the phenomenon of interest, while shorter, femtosecond (10-15 s) probe pulses are sampling its state at an adjustable time delay in order to reconstruct the dynamics of the system.
There are several possibilities for TP IV projects, some of a more technical nature, such as setting up a flexible cryogenic heat link, a fast laser beam modulator or advanced magneto-optic detection. Please get in touch directly with Gregor Jotzu if you are interested.
Below are some possibilities for Master’s projects.
- Real Magnetic Fields from Quantum Materials Driven by Bright Circularly Polarized Terahertz Pulses
The student will join our experimental research effort on one of our projects : driving chiral phonons with light in order to generate optically-controlled magnetic fields. We will use circularly polarized THz pulses to resonantly drive chiral phonons, i.e. rotating lattice vibrations. Theoretical works predict that these phonons should couple to the spins in the material. However, whether or not this translates into a real magnetic field around the sample is still debated. We will experimentally explore these ideas using new optical magnetometry approaches. Beyond the consequences for fundamental physics, these experiments will enable us to control magnetic fields on ultrafast (picosecond) timescale, with potentially far reaching applications in magnetic memories, quantum computing and ultrafast sensing.
Depending on her/his personal tastes and background, the student will work on more specific aspects of the research, for instance conduct calculations and simulations of the optical or electromagnetic processes at play, or help with the scientific instrumentation. The student will thus acquire technical skills in designing and constructing complex optical setups, nonlinear optics, and THz generation and characterization. She/he will be fully integrated in the scientific life of the laboratory.
- Optical Control of Quantized Magnetic Flux
The student will join our experimental research effort in controlling the magnetic flux in superconductors using light. In ring-shaped superconductors, the continuity of the electronic wavefunction results in quantization of the magnetic flux in the ring. The resulting fluxons could be a platform for scalable quantum computing devices, and are the building blocks of ultraprecise magnetic field sensors. Our experiment consist in allowing flux penetration in the ring using ultrafast, intense laser pulse that destroy superconductivity in a controlled manner. By tuning the intensity and repetition rate of the laser pulses, we could add or remove a single quantum of flux on femtosecond timescales. The magnetic field in the ring will be probed by optical magnetometry techniques. Beyond the consequences for fundamental physics, this approach may open new regimes of sensing in the active domain of ultrafast control of materials. Moreover, it will prepare the stage for a possible next generation of quantum computers operating at higher speeds and with more tunability.
Depending on her/his personal tastes and background, the student will also work on more specific aspects of the research, for instance conduct calculations and simulations of the optical or electromagnetic processes at play, or help with the scientific instrumentation. The student will thus acquire technical skills in designing and constructing complex optical setups, operating vacuum pumps and cryostats, and a knowledge of superconductivity. She/he will be fully integrated in the scientific life of the laboratory.