Abstract-THz streak camera method for synchronous arrival time measurement of two-color hard X-ray FEL pulses

Ishkhan Gorgisyan, Rasmus Ischebeck, Christian Erny, Andreas Dax, Luc Patthey, Claude Pradervand, Leonardo Sala, Christopher Milne, Henrik T. Lemke, Christoph P. Hauri, Tetsuo Katayama, Shigeki Owada, Makina Yabashi, Tadashi Togashi, Rafael Abela, Leonid Rivkin, and Pavle Juranić

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-25-3-2080&origin=search

The two-color operation of free electron laser (FEL) facilities allows the delivery of two FEL pulses with different energies, which opens new possibilities for user experiments. Measuring the arrival time of both FEL pulses relative to the external experimental laser and to each other improves the temporal resolution of the experiments using the two-color FEL beam and helps to monitor the performance of the machine itself. This work reports on the first simultaneous measurement of the arrival times of two hard X-ray FEL pulses with the THz streak camera. Measuring the arrival time of the two FEL pulses, the relative delay between them was calculated and compared to the set values. Furthermore, we present the first comparison of the THz streak camera method to the method of FEL induced transient transmission. The results indicate a good agreement between the two methods.

© 2017 Optical Society of America

Abstract-Generation of broadband THz pulses in organic crystal OH1 at room temperature and 10 K

Andrei G. Stepanov, Clemens Ruchert, Julien Levallois, Christian Erny, and Christoph P. Hauri  »View Author Affiliations http://www.opticsinfobase.org/ome/abstract.cfm?uri=ome-4-4-870

Optical Materials Express, Vol. 4, Issue 4, pp. 870-875 (2014)
http://dx.doi.org/10.1364/OME.4.000870

We studied the effects of cryogenic cooling of a 2-[3-(4-hydroxystyryl)-5, 5-dimethylcyclohex-2-enylidene] malononitrile (OH1) crystal on the generation of broadband THz pulses via collinear optical rectification of 1350 nm femtosecond laser pulses. Cooling of the OH1 crystal from room temperature to 10 K leads to a ~10% increase of the pump-to-THz energy conversion efficiency and a shift of the THz pulse spectra to a higher frequency range. Both effects are due the temperature variation of THz absorption and the refractive index of the OH1 crystal. This conclusion has been verified by temperature dependent measurements of the linear absorption in the THz frequency region. An approach to obtain a stronger increase of the THz generation efficiency at cryogenic cooling of the OH1 crystal is discussed.

© 2014 Optical Society of America