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Publikationen von
Burgard Beleites

Alle Publikationen des HI Jena

2021

L. Du, F. Roeder, Y. Li, M. Shalaby, B. Beleites, F. Ronneberger, and A. Gopal
Organic crystal-based THz source for complex refractive index measurements of window materials using single-shot THz spectroscopy
Applied Physics A 127, 846 (2021)

Abstract: We employed N-benzyl-2-methyl-4-nitroaniline (BNA) crystals bonded on substrates of different thermal conductivity to generate THz radiation by pumping with 800 nm laser pulses. Crystals bonded on sapphire substrate provided four times more THz yield than glass substrate. A pyrodetector and a single-shot electro-optic (EO) diagnostic were employed for measuring the energy and temporal characterisation of the THz pulse. Systematic studies were carried out for the selection of a suitable EO crystal, which allowed accurate determination of the emitted THz spectrum from both substrates. Subsequently, the THz source and single-shot electro-optic detection scheme were employed to measure the complex refractive index of window materials in the THz range.

M. Almassarani, S. Meng, B. Beleites, F. Ronneberger, G. Paulus, and A. Gopal
Parametric Study of Proton Acceleration from Laser-Thin Foil Interaction
Plasma 4, 670 (2021)

Abstract: We experimentally investigated the accelerated proton beam characteristics such as maximum energy and number by varying the incident laser parameters. For this purpose, we varied the laser energy, focal spot size, polarization, and pulse duration. The proton spectra were recorded using a single-shot Thomson parabola spectrometer equipped with a microchannel plate and a high-resolution charge-coupled device with a wide detection range from a few tens of keV to several MeV. The outcome of the experimental findings is discussed in detail and compared to other theoretical works.

2020

F. Roeder, M. Shalaby, B. Beleites, F. Ronneberger, and A. Gopal
THz generation by optical rectification of intense near-infrared pulses in organic crystal BNA
Optics Express 28, 36274 (2020)

Abstract: Generation of terahertz radiation by optical rectification of intense near-infrared laser pulses in N-benzyl-2-methyl-4-nitroaniline (BNA) is investigated in detail by carrying out a complete characterization of the terahertz radiation. We studied the scaling of THz yield with pump pulse repetition rate and fluence which enabled us to predict the optimal operating conditions for BNA crystals at room temperature for 800 nm pump wavelength. Furthermore, recording the transmitted laser spectrum allowed us to calculate the nonlinear refractive index of BNA at 800 nm.

2018

A. H. Woldegeorgis, B. Beleites, F. Ronneberger, R. Grosse, and A. Gopal
Investigating the influence of incident laser wavelength and polarization on particle acceleration and terahertz generation
Physical Review E 98, 061201 (2018)

Abstract: The interaction of a high-power laser pulse with a thin foil can generate energetic, broadband terahertz radiation. Here, we report an experimental investigation on the influence of incident laser polarization and wavelength on the terahertz emission and maximum proton energy from the target rear surface. For similar incident laser intensities, the characteristics of the particle beams and the terahertz radiation show a wavelength dependence. The results fit well with the established scaling laws for the terahertz yield and the maximum proton energy as a function of the incident laser irradiance.