2 research outputs found
Dynamics of four-photon photoluminescence in gold nanoantennas
Two-pulse correlation is employed to investigate the temporal dynamics of
both two-photon photoluminescence (2PPL) and four-photon photoluminescence
(4PPL) in resonant and nonresonant nanoantennas excited at a wavelength of 800
nm. Our data are consistent with the same two-step model being the cause of
both 4PPL and 2PPL, implying that the first excitation step in 4PPL is a
three-photon sp->sp direct interband transition. Considering energy and parity
conservation, we also explain why 4PPL behavior is favored over three-and
five-photon photoluminescence in the power range below the damage threshold of
our antennas. Since sizeable 4PPL requires larger peak intensities of the local
field, we are able to select either 2PPL or 4PPL in the same gold nanoantennas
by choosing a suitable laser pulse duration. We thus provide a first consistent
model for the understanding of multiphoton photoluminescence generation in gold
nanoantennas, opening new perspectives for applications ranging from the
characterization of plasmonic resonances to biomedical imaging
Nanoantennas for visible and infrared radiation
Nanoantennas for visible and infrared radiation can strongly enhance the
interaction of light with nanoscale matter by their ability to efficiently link
propagating and spatially localized optical fields. This ability unlocks an
enormous potential for applications ranging from nanoscale optical microscopy
and spectroscopy over solar energy conversion, integrated optical
nanocircuitry, opto-electronics and density-ofstates engineering to
ultra-sensing as well as enhancement of optical nonlinearities. Here we review
the current understanding of optical antennas based on the background of both
well-developed radiowave antenna engineering and the emerging field of
plasmonics. In particular, we address the plasmonic behavior that emerges due
to the very high optical frequencies involved and the limitations in the choice
of antenna materials and geometrical parameters imposed by nanofabrication.
Finally, we give a brief account of the current status of the field and the
major established and emerging lines of investigation in this vivid area of
research.Comment: Review article with 76 pages, 21 figure