Lecturer: Mr. Moshe Harats
Affiliation: Racah Institute of Physics,
The Hebrew University of Jerusalem
Abstract:
In recent years, there has been a great
effort in shaping the emission pattern of
colloidal Nanocrystal Quantum Dots (NQDs)
to utilize them as efficient light sources
down to the single photon level. The
advantage of NQDs in this matter stems
from their high quantum yield, the
possibility to change the emission
wavelength by changing their size, the
Stokes shift between the excitation
wavelength and the emission wavelength,
and their operation as single photon
emitters in room temperature. In order to
exploit the promising features of NQDs, one
needs to overcome the isotropic emission
pattern.
In this talk I will present two different
designs for the collimation of emission from
NQDs – a circular plasmonic lens and a
hybrid structure consisted of a plasmonic
lens with a dielectric layer. The different
samples are measured using a spectrally
resolved k-space imaging technique [1,2]
and in both cases we show a record high
collimation effect of 4° divergence angle.
We calculate the far-field emission pattern
using a semi-analytical calculation [3] and
FDTD simulations with very good agreement
with the experimental results. In addition, a
Hanbury-Brown-Twiss measurement was
performed to show that the emission is
from a single NQD. A value of g⁽²⁾(0)<0.5 was
achieved which indicates a single NQD
emission from the hybrid nanoantenna.
[1]M. G. Harats, N. Livneh, G. Zaiats, S.
Yochelis, Y. Paltiel, E. Lifshitz, and R.
Rapaport, Nano Lett. 14, 5766 (2014).
[2]A. Tittl, M. G. Harats, R. Walter, X. Yin,
M. Schäferling, N. Liu, R. Rapaport, and
H. Giessen, ACS Nano 8, 10885 (2014).
[3]L. Martin-Moreno, F. J. Garcia-Vidal, H.
J. Lezec, A. Degiron, and T. W. Ebbesen,
Phys. Rev. Lett. 90, 167401 (2003).