Bormann, Reiner

[["dc.bibliographiccitation.artnumber","241412"],["dc.bibliographiccitation.issue","24"],["dc.bibliographiccitation.journal","Physical Review. B"],["dc.bibliographiccitation.volume","95"],["dc.contributor.author","Danz, Thomas"],["dc.contributor.author","Neff, Andreas"],["dc.contributor.author","Gaida, John H."],["dc.contributor.author","Bormann, Reiner"],["dc.contributor.author","Ropers, Claus"],["dc.contributor.author","Schäfer, Sascha"],["dc.date.accessioned","2020-12-10T18:25:04Z"],["dc.date.available","2020-12-10T18:25:04Z"],["dc.date.issued","2017"],["dc.description.abstract","Electronic pseudospin degrees of freedom in two-dimensional materials exhibit unique carrier-field interactions which allow for advanced control strategies. Here, we investigate ultrafast sublattice pseudospin relaxation in graphene by means of polarization-resolved photoluminescence spectroscopy. A comparison with microscopic Boltzmann simulations allows us to determine a lifetime of the optically aligned pseudospin distribution of 12 +/- 2 fs. This experimental approach extends the toolbox of graphene pseudospintronics, providing additional means to investigate pseudospin dynamics in active devices or under external fields."],["dc.identifier.doi","10.1103/PhysRevB.95.241412"],["dc.identifier.eissn","2469-9969"],["dc.identifier.isi","000404470200003"],["dc.identifier.issn","2469-9950"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/75565"],["dc.language.iso","en"],["dc.notes.intern","DOI Import GROB-354"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","PUB_WoS_Import"],["dc.publisher","Amer Physical Soc"],["dc.relation.issn","2469-9969"],["dc.relation.issn","2469-9950"],["dc.title","Ultrafast sublattice pseudospin relaxation in graphene probed by polarization-resolved photoluminescence"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.contributor.author","Feist, Armin"],["dc.contributor.author","Echternkamp, Katharina E."],["dc.contributor.author","Bormann, Reiner"],["dc.contributor.author","Rubiano da Silva, Nara"],["dc.contributor.author","Möller, Marcel"],["dc.contributor.author","Liang, Wenxi"],["dc.contributor.author","Schäfer, Sascha"],["dc.contributor.author","Ropers, Claus"],["dc.date.accessioned","2020-02-03T09:17:06Z"],["dc.date.available","2020-02-03T09:17:06Z"],["dc.date.issued","2016"],["dc.description.abstract","We demonstrate the generation of low-emittance ultrashort electron pulses derived from nanoscale photocathodes and their application in ultrafast transmission electron microscopy. Few-nanometer electron focal spot diameters are achieved, enabling the investigation of ultrafast nanoscale dynamics."],["dc.identifier.doi","10.1364/up.2016.uth2b.5"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/62937"],["dc.language.iso","en"],["dc.publisher","OSA - The Optical Society"],["dc.publisher.place","Washington, D.C."],["dc.relation.conference","International Conference on Ultrafast Phenomena 2016"],["dc.relation.eventend","2016-07-22"],["dc.relation.eventlocation","Santa Fe, New Mexico United States"],["dc.relation.eventstart","2016-07-17"],["dc.relation.isbn","978-1-943580-18-7"],["dc.relation.ispartof","Proceedings of the International Conference on Ultrafast Phenomena 2016"],["dc.title","Few-nanometer femtosecond electron probe pulses in ultrafast transmission electron microscop"],["dc.type","conference_paper"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","231105"],["dc.bibliographiccitation.issue","23"],["dc.bibliographiccitation.journal","Applied Physics Letters"],["dc.bibliographiccitation.volume","107"],["dc.contributor.author","Schroeder, Benjamin"],["dc.contributor.author","Sivis, Murat"],["dc.contributor.author","Bormann, Reiner"],["dc.contributor.author","Schäfer, Sascha"],["dc.contributor.author","Ropers, Claus"],["dc.date.accessioned","2018-11-07T09:47:38Z"],["dc.date.available","2018-11-07T09:47:38Z"],["dc.date.issued","2015"],["dc.description.abstract","We demonstrate multiphoton photoelectron emission from gold nanotips induced by nanofocusing surface plasmons, resonantly excited on the tip shaft by a grating coupler. The tip is integrated into an electron gun assembly, which facilitates control over the spatial emission sites and allows us to disentangle direct grating emission from plasmon-triggered apex emission. The nanoscale source size of this electron gun concept enables highly coherent electron pulses with applications in ultrafast electron imaging and diffraction. (C) 2015 AIP Publishing LLC."],["dc.description.sponsorship","Deutsche Forschungsgemeinschaft (DFG) [SFB-1073]"],["dc.identifier.doi","10.1063/1.4937121"],["dc.identifier.isi","000367010800005"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/35153"],["dc.language.iso","en"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation","SFB 1073: Kontrolle von Energiewandlung auf atomaren Skalen"],["dc.relation","SFB 1073 | Topical Area A | A05 Nanoskalige Untersuchung raumzeitlicher Relaxation in heterogenen Systemen mit ultraschneller Transmissionselektronenmikroskopie"],["dc.relation.issn","1077-3118"],["dc.relation.issn","0003-6951"],["dc.title","An ultrafast nanotip electron gun triggered by grating-coupled surface plasmons"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","63"],["dc.bibliographiccitation.journal","Ultramicroscopy"],["dc.bibliographiccitation.lastpage","73"],["dc.bibliographiccitation.volume","176"],["dc.contributor.author","Feist, Armin"],["dc.contributor.author","Bach, Nora"],["dc.contributor.author","da Silva, Nara Rubiano"],["dc.contributor.author","Danz, Thomas"],["dc.contributor.author","Möller, Marcel"],["dc.contributor.author","Priebe, Katharina E."],["dc.contributor.author","Domröse, Till"],["dc.contributor.author","Gatzmann, J. Gregor"],["dc.contributor.author","Rost, Stefan"],["dc.contributor.author","Schauss, Jakob"],["dc.contributor.author","Strauch, Stefanie"],["dc.contributor.author","Bormann, Reiner"],["dc.contributor.author","Sivis, Murat"],["dc.contributor.author","Schäfer, Sascha"],["dc.contributor.author","Ropers, Claus"],["dc.date.accessioned","2018-11-07T10:23:59Z"],["dc.date.accessioned","2020-02-03T09:08:33Z"],["dc.date.available","2018-11-07T10:23:59Z"],["dc.date.available","2020-02-03T09:08:33Z"],["dc.date.issued","2017"],["dc.description.abstract","We present the development of the first ultrafast transmission electron microscope (UTEM) driven by localized photoemission from a field emitter cathode. We describe the implementation of the instrument, the photoemitter concept and the quantitative electron beam parameters achieved. Establishing a new source for ultrafast TEM, the Göttingen UTEM employs nano-localized linear photoemission from a Schottky emitter, which enables operation with freely tunable temporal structure, from continuous wave to femtosecond pulsed mode. Using this emission mechanism, we achieve record pulse properties in ultrafast electron microscopy of 9Å focused beam diameter, 200fs pulse duration and 0.6eV energy width. We illustrate the possibility to conduct ultrafast imaging, diffraction, holography and spectroscopy with this instrument and also discuss opportunities to harness quantum coherent interactions between intense laser fields and free-electron beams."],["dc.identifier.arxiv","1611.05022v1"],["dc.identifier.doi","10.1016/j.ultramic.2016.12.005"],["dc.identifier.isi","000403992200010"],["dc.identifier.pmid","28139341"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/42570"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/62933"],["dc.language.iso","en"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","PUB_WoS_Import"],["dc.relation","SFB 1073: Kontrolle von Energiewandlung auf atomaren Skalen"],["dc.relation","SFB 1073 | Topical Area A | A05 Nanoskalige Untersuchung raumzeitlicher Relaxation in heterogenen Systemen mit ultraschneller Transmissionselektronenmikroskopie"],["dc.relation.eissn","1879-2723"],["dc.relation.issn","0304-3991"],["dc.rights","CC BY-NC-ND 4.0"],["dc.title","Ultrafast transmission electron microscopy using a laser-driven field emitter: Femtosecond resolution with a high coherence electron beam"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.subtype","original_ja"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","173105"],["dc.bibliographiccitation.issue","17"],["dc.bibliographiccitation.journal","Journal of Applied Physics"],["dc.bibliographiccitation.volume","118"],["dc.contributor.author","Bormann, Reiner"],["dc.contributor.author","Strauch, Stefanie"],["dc.contributor.author","Schäfer, Sascha"],["dc.contributor.author","Ropers, Claus"],["dc.date.accessioned","2018-11-07T09:49:01Z"],["dc.date.available","2018-11-07T09:49:01Z"],["dc.date.issued","2015"],["dc.description.abstract","We experimentally and numerically investigate the performance of an advanced ultrafast electron source, based on two-photon photoemission from a tungsten needle cathode incorporated in an electron microscope gun geometry. Emission properties are characterized as a function of the electrostatic gun settings, and operating conditions leading to laser-triggered electron beams of very low emittance (below 20 nm mrad) are identified. The results highlight the excellent suitability of optically driven nano-cathodes for the further development of ultrafast transmission electron microscopy. (C) 2015 AIP Publishing LLC."],["dc.identifier.doi","10.1063/1.4934681"],["dc.identifier.isi","000364584200005"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/35426"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation","SFB 1073: Kontrolle von Energiewandlung auf atomaren Skalen"],["dc.relation","SFB 1073 | Topical Area A | A05 Nanoskalige Untersuchung raumzeitlicher Relaxation in heterogenen Systemen mit ultraschneller Transmissionselektronenmikroskopie"],["dc.relation.issn","1089-7550"],["dc.relation.issn","0021-8979"],["dc.title","An ultrafast electron microscope gun driven by two-photon photoemission from a nanotip cathode"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]