Ultrafast nanooptics

Antenna enhanced coherent control of currents in nanostructures (Betz)

Phase-related optical beams have advanced the application of light in a broad variety of physical processes. Here, we investigate coherent control of ballistic electrical currents in hybrid semiconductor/metal antenna devices with phase-related femtosecond w/2w near-infrared pulse pairs. While two-color schemes utilizing a quantum interference of one- and two-photon absorption pathways are known to efficiently induce currents in bulk materials, their applicability to nanodevices is unexplored. In particular, we will exploit the field enhancement of metallic antenna structures to (i) effectively enhance current injection associated with the third order optical nonlinearity and (ii) confine ballistic currents to sub-wavelength dimensions. First, currents will be induced in the gap of metallic bow tie antennas deposited on GaAs. Their vector direction is controlled by the polarization and relative phase within the excitation field. Currents will be characterized by the voltage drop between the two antenna parts induced by charge accumulation. Then, we will suspend single carbon nanotubes across the antenna and study all-optical generation of electrical current in unbiased nanotube devices. Finally, we will explore the possibility of current injection with single color pulses. In all steps, the devices will be characterized as a function of temperature as well as shape and material of the nano-antennas. The results are expected to provide exciting insight all-optical switching in various kinds of nanocircuits


Sub-diffraction optical coherent control of ultrafast electrical currents in antenna devices on GaAs
Sebastian Thunich, Claudia Ruppert, Alexander W. Holleitner, and Markus Betz
Applied Physics Letters 101 (2012) 251119
Coherent control of electrical currents in semiconductor nanowires/-tubes
M. Betz, C. Ruppert, S. Thunich, R. Newson, J.-M. Ménard, C. Sames, G. Abstreiter, A. Fontcuberta i Morral, A. W. Holleitner, H. M. van Driel
Physica Status Solidi C 8 (2011) 1224
Field-Resolved Characterization of Femtosecond Electromagnetic Pulses with 400 THz Bandwidth
S. Thunich, C. Ruppert, A. W. Holleitner, and M. Betz
Optics Letters 36 (2011) 1791
Quantum Interference Control of Femtosecond, µA Current Bursts in Single GaAs Nanowires
C. Ruppert, S. Thunich, A. Fontcuberta i Morral, A. W. Holleitner, and M. Betz
Nano Letters 10 (2010) 1799
Coherently controlled ballistic charge currents in single-walled carbon nanotubes and graphite
R. W. Newson, J.-M. Menard, C. Sames, M. Betz, and H. M. van Driel
Nano Letters 8 (2008) 1586
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