Showing posts with label
2-D time domain electromagnetism/transport simulator.
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Showing posts with label
2-D time domain electromagnetism/transport simulator.
Show all posts
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.
Christophe Dalle
http://onlinelibrary.wiley.com/doi/10.1002/jnm.2213/abstract
The potential of gallium nitride–distributed transferred electron device is theoretically investigated for the realization of terahertz radio frequency (RF) power sources. The device numerical physical modeling relies on a 2D time-domain electromagnetism/transport simulator. It is based on the coupled solution of the Maxwell and energy-momentum macroscopic transport equations. The study is focused on the analysis of the device complex internal RF operation. The device technological and geometrical structure is optimized for an RF operation at 1 THz. The time and space, local and functional quantities are analyzed following both electromagnetic and quasi-electrostatic approaches. We finally conclude on the feasibility of such a device.
