Ultrashort laser pulse interaction with target: ion acceleration

December 12, 2017

Institute of Physics, University of Pécs and the Committee on Physics and Astronomy, Regional Committee in Pécs, Hungarian Academy of Sciences warmly invites you to attend the presentation of

Sargis Ter-Avetisyan

(ELI-ALPS)

Ultrashort laser pulse interaction with target: ion acceleration

Location: Faculty of Sciences, UP, Room E/421

Date and time: Tuesday, December 12, 2017, 10:30

Summary: Experiments on ion acceleration driven by high intensity lasers over the past ~15 years have demonstrated the generation of multi-10s of MeV proton and ion beams with remarkable properties such as ultrashort burst emission, high brilliance, and low emittance over a wide range of laser and target parameters.
Nowadays the laser peak power can reach several petawatts (PW) and the intensity above 1022 W/cm2 can become available for experiments. Thus, an entirely new area of research, the regime of relativistic plasma physics became accessible in the lab. To explore the interaction physics in these novel intensity regime is one of the most exciting goals of current high field research. After short survey of relevant background, this presentation will discuss the recent experimental findings on ion acceleration obtained on PW laser.
In most laser-driven ion acceleration studies the sheath field established by relativistic electrons at target surface accelerates ions via the so-called Target Normal Sheath Acceleration (TNSA). A separate mechanism, Radiation Pressure Acceleration (RPA) where radiation pressure is exerted via laser ponderomotive force on a foil surface, which results in electron-ion displacement and ion acceleration via the ensuing space-charge field. At PW laser power a new scenario was found, which offers more favorable proton energy scaling with laser intensity than "ordinary" TNSA. The ions are accelerated in the electrostatic field of charged cavity created by relativistic laser pulse at the target front and in the enhanced sheath field at the target rear.
This new, highly relativistic plasma regime have stimulated the emergence of a new ideas and advanced diagnostic development for measuring plasma effects not even thought today. We will discuss the comprehensive on-line diagnostic systems allowing an extensive and thorough research of laser-plasma processes, providing essential information on their complex dynamics.
This presentation is closely related to recent development or imminently anticipated development of laser technology to bring the existing laser systems to a multi-PW level. Recent findings pave a way to achieving an ion source and beam desire parameters and they encourage further activities for optimisation of laser plasmabased accelerators..

Enhanced detection of weak terahertz signal from bacteriorhodopsin by electro-optic sampling

November 16, 2017

Institute of Physics, University of Pécs and the Committee on Physics and Astronomy, Regional Committee in Pécs, Hungarian Academy of Sciences warmly invites you to attend the presentation of

Shaoxian Li

(University of Pécs, Institute of Physics)

Enhanced detection of weak terahertz signal from bacteriorhodopsin by electro-optic sampling

Location: Faculty of Sciences, UP, Room A/401

Date and time: Tuesday, November 11, 2017, 12:00

RIKEN intense terahertz-wave source and sensitive detection

June 1st, 2017

Institute of Physics, University of Pécs and the Committee on Physics and Astronomy, Regional Committee in Pécs, Hungarian Academy of Sciences warmly invites you to attend the presentation of

Hiroaki Minamide

(RIKEN Center for Advanced Photonics)

RIKEN intense terahertz-wave source and sensitive detection

Location: Faculty of Sciences, UP, Room A/421

Date and time: Friday, June 9th, 2017, 10:00

Abstract: Terahertz (THz)-wave technology has gradually advanced on the basis of nonlinear optics and ultra-fast photonics. Intense THz waves are generated using a nonlinear optical crystal, especially LiNbO3. Recently, our studies on injection-seeded THz-wave parametric source [1] show wavelength tunability in the range from 0.8 THz to 4.7 THz with less than 5 GHz linewidth. By using a trapezoidal crystal, the gain area of THz-wave emission was extremely close to the crystal surface, which could successfully reduce the THz-wave absorption by the crystal.
In inverse wavelength conversion, THz-wave photons are efficiently converted into near-infrared photons, which provides sensitive THz-wave detection at the attojoule level. Recently, THz-wave emission from a resonant tunneling diode (RTD) has been detected by the nonlinear up-conversion technique [2].

Acknowledgements: I would like to thank all the members of Tera-Photonics Research Team, RAP, RIKEN, and research collaborators. This work was partially supported by JSPS KAKENHI Grant Numbers 17H01282, 15K18079, 25220606, 26390106, 15K18080, 26246046, 26287067, and 25286075. We gratefully acknowledge ImPACT Program of Council for Science, Technology and Innovation (Cabinet Office, Government of Japan).

References
[1] S. Hayashi, K. Nawata, T. Taira, J. Shikata, K. Kawase, and H. Minamide, Ultrabright continuously tunable terahertz-wave generation at room temperature, Scientific Reports, 4, 05045, 2014.
[2] Y. Takida, K. Nawata, S. Suzuki, M. Asada, and H. Minamide, Terahertz-wave differential detection based on simultaneous dual-wavelength up-conversion, AIP Advances, 7, 035020, 2017.

Ionisation processes of Rubidium in strong electromagnetic fields

November 23rd, 2016

Institute of Physics, University of Pécs and the Committee on Physics and Anstronomy, Regional Committee in Pécs, Hungarian Academy of Sciences warmly invites you to attend the presentation of

Mihály Pocsai

(Institute of Physics, UP, and Wigner Research Centre for Physics, HAS)

Ionisation processes of Rubidium in strong electromagnetic fields

Location: Faculty of Sciences, UP, Room A/408

Date and time: Friday, November 25th, 2016, 12:30

Summary: We investigate the ionisation processes of rubidium in strong infra-red laser fields and in the electromagnetic field of a 400 GeV energy proton beam via ab initio calculations.We reduce the latter phenomena to photoionisation with the Weizsäcker–Williams method. The bound and the continuum states are described with Slater orbitals and Coulomb wavepackets, respectively. The bound state spectrum has been calculated with the variational method. Using this approach, ionisation processes can be studied successfully [1]. We investigate the effects of the shape and the parameters of the pulse to the photoionisation cross section. These calculations may provide a valuable contribution at the design of laser and plasma based novel accelerators, e.g. the CERN AWAKE experiment [2].

References
[1] I.F. Barna, J. Wang, J. Burgdörfer, Phys. Rev. A 73, 023402 (2006)
[2] E.Gschwendtner et al.: Proceedings of IPAC 2014, Dresden, Germany (2014), The AWAKE Experimental Facility at CERN.

A compact source of extremely strong terahertz fields

October 25th, 2016

A publication by the members of the MTA-PTE High-Field Terahertz Research Group and the Institute of Physics in Optica journal

Researchers of the PTE SZKK High-Field Terahertz Research Group developed a compact, semiconductor terahertz radiation source, which enabled to increase the efficiency by more than hundred times. The source is pumped at an infrared wavelength and utilizes a unique optical grating for the generation of terahertz pulses with extremely high electric field. The work opens up new perspectives for strong-field control of matter and for constructing compact particle accelerators for materials science and medicine.

The publication has also been highlighted on the cover of the Optica journal.

J. A. Fülöp et al., Optica 3, 1075 (2016)

Public defense of the PhD thesis of Judit Sári

May 9th, 2016

The Institute of Physics invites you to the public defense of the PhD thesis entitled Excitations of Quasi-Two-Dimensional Electron Systems in Magnetic Field written by Judit Sári.

The defense takes place on Tuesday, May 17th, 2016, at Room A/408, Faculty of Sciences, University of Pécs (Pécs, Ifjúság str. 6).

Jedlik Ányos Award was conferred to Dr. János Hebling

March 17th, 2016

On the occasion of our national day, 15th of March, Jedlik Ányos Award-Giving Ceremony took place on the 9th of March at the ceremonial hall of the Hungarian Academy of Sciences. This year the prestigious award was conferred to the professor of our Faculty, the director of our Institute, Dr. János Hebling.