Abstract-Spin preservation during THz orbital pumping of shallow donors in silicon

Kamyar Saeedi, Nikolas Stavrias, Britta Redlich, A.F.G. van der Meer, Rostislav Mikhaylovskiy, Alexey V Kimel, C R Pidgeon,  B N Murdin

https://iopscience.iop.org/article/10.1088/1361-648X/ab31d2/pdf

We investigate the spin relaxation under conditions of optical excitation between the Rydberg orbital states of phosphorus donor impurities in silicon. Here we show that the spin relaxation is less than a few percent, even after multiple excitation/relaxation cycles. The observed high level of spin preservation may be useful for readout cycling or in quantum information schemes where coupling of neighbor qubits is via orbital excitation.

Abstract-Molecular Alignment of Bulk Water: Observing a Giant THz Kerr Effect upon Librational Excitation

Fabio Novelli, Federico Sebastiani, Claudius Hoberg, Luis Ruiz Pestana, Kochise C. Bennett, Nikolas Stavrias, Lex A.F.G. Van Der Meer, Gerhard Schwaab, Teresa Head-Gordon, Martina Havenith

https://arxiv.org/abs/1809.04261

Induced orientation of a molecule in real space by static and intense laser fields has been successfully employed to control reactions in the gas phase. However, for bulk water an effective alignment was not realized, yet due to the fast energy dissipation into the water network. Here we report a nonlinear Terahertz (THz) experiment carried out at the free electron laser FELIX. At 11.7 THz we observe a giant, resonance enhanced Kerr parameter which exceeds previous values by 4 orders of magnitude. Using ab initio molecular dynamics calculations, the large THz Kerr effect can be rationalized in terms of a linear response of a driven resonance orientation upon excitation of single water rotations. Our results suggest that bulk water can be efficiently aligned by THz laser fields around 12 THz.