Attosecond-controlled photoemission from metal nanowire tips in the few-electron regime
Okell, W. A.
Di Fabrizio, Enzo M.
Kling, M. F.
KAUST DepartmentPhysical Sciences and Engineering (PSE) Division
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AbstractMetal nanotip photoemitters have proven to be versatile in fundamental nanoplasmonics research and applications, including, e.g., the generation of ultrafast electron pulses, the adiabatic focusing of plasmons, and as light-triggered electron sources for microscopy. Here, we report the generation of high energy photoelectrons (up to 160 eV) in photoemission from single-crystalline nanowire tips in few-cycle, 750-nm laser fields at peak intensities of (2-7.3) × 1012 W/cm2. Recording the carrier-envelope phase (CEP)-dependent photoemission from the nanowire tips allows us to identify rescattering contributions and also permits us to determine the high-energy cutoff of the electron spectra as a function of laser intensity. So far these types of experiments from metal nanotips have been limited to an emission regime with less than one electron per pulse. We detect up to 13 e/shot and given the limited detection efficiency, we expect up to a few ten times more electrons being emitted from the nanowire. Within the investigated intensity range, we find linear scaling of cutoff energies. The nonlinear scaling of electron count rates is consistent with tunneling photoemission occurring in the absence of significant charge interaction. The high electron energy gain is attributed to field-induced rescattering in the enhanced nanolocalized fields at the wires apex, where a strong CEP-modulation is indicative of the attosecond control of photoemission.
CitationAhn B, Schötz J, Kang M, Okell WA, Mitra S, et al. (2017) Attosecond-controlled photoemission from metal nanowire tips in the few-electron regime. APL Photonics 2: 036104. Available: http://dx.doi.org/10.1063/1.4974529.
SponsorsWe thank Peter Hommelhoff for very fruitful discussions and Seungchul Kim for help with the nanowire samples. We are grateful for support by the Max Planck Society and the DFG through LMUexcellent, SPP1840 “QUTIF,” and the Cluster of Excellence: “Munich Centre for Advanced Photonics (MAP).” B.F. acknowledges support from Marco Allione and Enzo Di Fabrizio via the King Abdullah University of Science and Technology (KAUST). B.F., S.M., S.Z., M.K., F.S., and M.F.K. acknowledge support from the European Union via the ERC grant ATTOCO (Grant No. 307203). This research has been supported in part by Global Research Laboratory Program (Grant No 2009-00439) and by Max Planck POSTECH/KOREA Research Initiative Program (Grant No 2016K1A4A4A01922028) through the National Research Foundation of Korea (NRF) funded by Ministry of Science, ICT & Future Planning.
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