|Title:||Terahertz phonon mode engineering of highly efficient organic terahertz generators|
|Authors :||Lee, Seung-Heon|
Kang, Bong Joo
|Published in :||Advanced Functional Materials|
|Publisher / Ed. Institution :||Wiley|
|License (according to publishing contract) :||Licence according to publishing contract|
|Type of review:||Peer review (Publication)|
|Subject (DDC) :||530: Physics |
|Abstract:||For terahertz (THz) wave generators based on organic electrooptic crystals, their intrinsic phonon modes are playing an essential role in THz generation characteristics. Here, this study proposes an effective design strategy for THz phonon mode engineering of organic electrooptic salt crystals for efficient optical-to-THz frequency conversion. To reduce phonon-mode intensity, strongly electronegative trifuoromethyl group acting as strong hydrogen-bond acceptor is incorporated into molecular anions. New 2-(4-hydroxy-3-methoxystyryl)-1-methylquinolinium 4-(trifuoromethyl)benzenesulfonate (HMQ-4TFS) crystals exhibit a relatively small absorption coefficient in the THz spectral range between 0.5 and 4 THz, which is attributed to suppressed molecular vibrations due to strong hydrogen bonds involving the 4TFS anion. In addition, HMQ-4TFS crystals possess a very large macroscopic optical nonlinearity, comparable (or even higher) to benchmark stilbazolium crystals. Based on the low-intensity THz phonon modes and the large optical nonlinearity, a 0.37 mm thick HMQ-4TFS crystal pumped with 150 fs infrared laser pulses facilitates very efficient THz wave generation by optical rectification, delivering 23 times higher peak-to-peak THz electric eld than the widely used standard inorganic ZnTe crystal (1.0 mm thick) and a broader spectral bandwidth. Therefore, strongly electronegative groups introduced into molecular salt electrooptic crystals provide a very promising design strategy of THz phonon mode engineering for developing intense broadband THz sources.|
|Departement:||School of Engineering|
|Organisational Unit:||Institute of Computational Physics (ICP)|
|Publication type:||Article in scientific Journal|
|Appears in Collections:||Publikationen School of Engineering|
Files in This Item:
There are no files associated with this item.
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.