Photon diagnostics at the FLASH THz beamline

The THz beamline at FLASH, DESY, provides both tunable (1 – 300   THz) narrow-bandwidth ( ∼ 10%) and broad-bandwidth intense (up to 150 uJ) THz pulses delivered in 1   MHz bursts and naturally synchronized with free-electron laser X-ray pulses. Combination of these pulses, along with the auxiliary NIR and VIS ultrashort lasers, supports a plethora of dynamic investigations in physics, material science and biology. The unique features of the FLASH THz pulses and the accelerator source, however, bring along a set of challenges in the diagnostics of their key parameters: pulse energy, spectral, temporal and spatial profiles. Here, these challenges are discussed and the pulse diagnostic tools developed at FLASH are presented. In particular, a radiometric power measurement is presented that enables the derivation of the average pulse energy within a pulse burst across the spectral range, jitter-corrected electro-optical sampling for the full spectro-temporal pulse characterization, spatial beam profiling along the beam transport line and at the sample, and a lamellar grating based Fourier transform infrared spectrometer for the on-line assessment of the average THz pulse spectra. Corresponding measurement results provide a comprehensive insight into the THz beamline capabilities.

Source: Journal of Synchrotron Radiation - April 25, 2019 Category: Physics Authors: Pan, R. Zapolnova, E. Golz, T. Krmpot, A.J. Rabasovic, M.D. Petrovic, J. Asgekar, V. Faatz, B. Tavella, F. Perucchi, A. Kovalev, S. Green, B. Geloni, G. Tanikawa, T. Yurkov, M. Schneidmiller, E. Gensch, M. Stojanovic, N. Tags: FLASH intense THz THz diagnostic electro-optic FTIR research papers Source Type: research