Extreme-ultraviolet coherent pulse amplification in argon

The amplification of ultrashort extreme-ultraviolet (XUV) pulses in argon in high-order harmonic generation processes is studied by using the time-dependent Schrödinger equation in the spin-free one-active-electron and single-atom approximation. We consider a neutral argon atom initially in the valence 3p state and a sufficiently intense two-cycle driving infrared (IR) pulse for the atom to be mainly ionized after the first laser cycle. The correlated dynamics and transitions from the valence 3p to a virtual subvalence 3s state and in the ionized regions are examined by synchronizing a 1.5-fs XUV pulse to the IR pulse. The calculated single-atom gain spectrum (26–45 eV) agrees with recent experimental measurements. We discuss different channels that can be present in the gain process as a function of pulse parameters and through an analysis of the dynamics of the populations in terms of field-free eigenstates. When the XUV pulse is considered at the end of the driving IR field the amplification is due to contributions of stimulated recombination from excited Rydberg and low energy continuum states to the 3s and 3p states of argon. In regions where the IR field is intense, high energy and angular momentum states are populated and the medium can interact with the pulses through bound and continuum states involving parametric transitions, which is further confirmed by studying classical electron trajectories. We discuss how these parametric interactions might be suitable for amplification of photon energies far from the ionization threshold as observed in the experiments.Peer ReviewedPostprint (author's final draft

Parametric attosecond pulse amplification far from the ionization threshold from high order harmonic generation in He+^+

Parametric amplification of attosecond coherent pulses around 100 eV at the single-atom level is demonstrated for the first time by using the 3D time-dependent Schr{\"o}dinger equation in high-harmonic generation processes from excited states of He$^+$. We present the attosecond dynamics of the amplification process far from the ionization threshold and resolve the physics behind it. The amplification of a particular central photon energy requires the seed XUV pulses to be perfectly synchronized in time with the driving laser field for stimulated recombination to the He$^+$ ground state and is only produced in a few specific laser cycles in agreement with the experimental measurements. Our simulations show that the amplified photon energy region can be controlled by varying the peak intensity of the laser field. Our results pave the way to the realization of compact attosecond pulse intense XUV lasers with broad applications

A romániai magyar külképviseletek (bukaresti követség, kolozsvári konzulátus, brassói és aradi konzulátus) 1921-1944 közötti iratanyagának feltárása, feldolgozása és kiadása = Publishing of the archival material of the Hungarian diplomatic missions (Hungarian embassy in Bucharest, Hungarian consulates in Kolozsvár, Brassó and Arad) in Rumania 1921-1944

A projekt 2008. máj. 1-től 2012. ápr. 30-ig tartó időszakában a levéltári forrásfeltárás nyomán összesen 13 publikáció jelent meg: 12 tanulmány és forrásközlemény, illetve 1 önálló kötet. Ezen kívül elkészült 1 önálló kötet kézirata bev. tan.-al, forrástárral, az azokhoz írt lábjegyz.-kel és annotált névmutatóval. Ld. Magyar katolikus szórványok a Kárpátokon túl. A Szent László Társulat tevékenysége a két világháború között. Az iratokat gyűjt. és vál., a bev. tan.-t, a lábjegyz.-ket és az annotált névmutatót írta: Seres Attila. Budapest, 2012. A kézirat nyomdai kiadásra készen áll. Elkészült továbbá 1 önálló kötet forrástára is. Ld. Márton Áron és az erdélyi katolikus püspökség a második bécsi döntés után. Magyar diplomáciai iratok 1940-1944. Az iratokat gyűjt. és vál.: Seres Attila. Budapest, 2012. A forrástárhoz a bev. tan.-t, a lábjegyz.-ket, illetve az annotált névmutatót még el kell készíteni. A megjelent publikációk, és a kéziratban lévő kötetek anyaga döntően magyar diplomáciai forrásokon, a bukaresti követség, a kolozsvári, az aradi, és a brassói konzulátus jelentésein alapul. A több fondban szétszórt magyar diplomáciai jelentések értékeléséhez más magyar iratanyagot, a Min.eln.-ség Nemzetiségi és Kisebbségi Osztályának, és a Szent László Társulatnak az iratait is felhasználtunk. Az ebből a forráskörből kibontakozó képet román levéltári forrásokkal, valamint a legújabb magyar és román szakirodalom eredményeivel árnyaltuk. | In the period from 1st of May 2008 to 30th of April 2012 as a result of investigations of archival sources 13 publications have been published altogether including 12 issues and 1 book. Beside these has been completed a typscript of a volume of documents including introduction chapter, footnotes and name index. See: Hungarian Catholics over the Carpaths. The activity of Szent László Society between the two world wars. Edyted by: Seres Attila. Budapest, 2012. The typesript is ready for publishing. Beside this also has been completed a collection of written sources. See: Márton Áron and the Transylvanian Catholic Episcopate after the Second Wienna Arbitrage. Hungarian diplomatical sources 1940-1944. Edited by: Seres Attila. Budapest, 2012. An introduction chapter, footnotes and a name index have to be written for publishing of this volume. All the published issues and volumes and unpublished typescripts based on Hungarian diplomatical sources, basically on the reports of the Hungarian Embassy in Bucharest, the Hungarian Consulate General in Kolozsvár, the Hungarian Consulates in Brassó and Arad. In order to summit of the Hungarian diplomatical sources housing in several archival fonds we also used other Hungarian archival sources like documents of the Department of Nationalities and Minorities at the Prime Ministry and documents of Szent László Society. We also analized the last results of the Hungarian and Romanian historiography and Romanian archival sources