TY - JOUR
T1 - Plasmonic nanostar photocathodes for optically-controlled directional currents
AU - Pettine, Jacob
AU - Choo, Priscilla
AU - Medeghini, Fabio
AU - Odom, Teri W.
AU - Nesbitt, David J.
N1 - Funding Information:
We would like to acknowledge Dr. K. Culver’s contributions to the nanostar synthesis process along with her role in stimulating these investigations. J.P., F.M., and D.J.N would also like to thank Prof. M. Müller and Prof. M. Raschke for illuminating conversations. Photoemission studies (D.J.N.) were supported by the Air Force Office of Scientific Research (FA9550-15-1-0090) with additional funds for laser development and apparatus construction provided by the National Science Foundation (CHE 1665271, PHY 1734006). Nanostar synthesis (T.W.O.) was supported by the National Science Foundation (CHE 1808502).
PY - 2020/12/1
Y1 - 2020/12/1
N2 - Plasmonic nanocathodes offer unique opportunities for optically driving, switching, and steering femtosecond photocurrents in nanoelectronic devices and pulsed electron sources. However, angular photocurrent distributions in nanoplasmonic systems remain poorly understood and are therefore difficult to anticipate and control. Here, we provide a direct momentum-space characterization of multiphoton photoemission from plasmonic gold nanostars and demonstrate all-optical control over these currents. Versatile angular control is achieved by selectively exciting different tips on single nanostars via laser frequency or linear polarization, thereby rotating the tip-aligned directional photoemission as observed with angle-resolved 2D velocity mapping and 3D reconstruction. Classical plasmonic field simulations combined with quantum photoemission theory elucidate the role of surface-mediated nonlinear excitation for plasmonic field enhancements highly concentrated at the sharp tips (Rtip = 3.4 nm). We thus establish a simple mechanism for femtosecond spatiotemporal current control in designer nanosystems.
AB - Plasmonic nanocathodes offer unique opportunities for optically driving, switching, and steering femtosecond photocurrents in nanoelectronic devices and pulsed electron sources. However, angular photocurrent distributions in nanoplasmonic systems remain poorly understood and are therefore difficult to anticipate and control. Here, we provide a direct momentum-space characterization of multiphoton photoemission from plasmonic gold nanostars and demonstrate all-optical control over these currents. Versatile angular control is achieved by selectively exciting different tips on single nanostars via laser frequency or linear polarization, thereby rotating the tip-aligned directional photoemission as observed with angle-resolved 2D velocity mapping and 3D reconstruction. Classical plasmonic field simulations combined with quantum photoemission theory elucidate the role of surface-mediated nonlinear excitation for plasmonic field enhancements highly concentrated at the sharp tips (Rtip = 3.4 nm). We thus establish a simple mechanism for femtosecond spatiotemporal current control in designer nanosystems.
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U2 - 10.1038/s41467-020-15115-0
DO - 10.1038/s41467-020-15115-0
M3 - Article
C2 - 32170067
AN - SCOPUS:85081746570
VL - 11
JO - Nature Communications
JF - Nature Communications
SN - 2041-1723
IS - 1
M1 - 1367
ER -