FYI.
Anna B. Shin
Laboratory Administrator | Aspuru-Guzik Research Group
Department of Chemistry and Chemical Biology | Harvard University
12 Oxford Street | Cambridge, MA 02138
617.496.9964 office | 617.694.9879 cell | 617.496.9411 fax
http://aspuru.chem.harvard.edu/<http://?ui=2&ik=e7480c62f0&view=…
---------- Forwarded message ----------
From: Marc Baldo <baldo(a)mit.edu>
Date: Wed, Oct 17, 2012 at 11:19 AM
Subject: FW: Finley Seminar, Thursday 11 a.m, Grier A (34-401a): Please
forward
To: excitonics-faculty(a)mit.edu
Cc: Catherine Bourgeois <cmbourg(a)mit.edu>
Hello everyone,****
This is an announcement for a seminar that many of us may find interesting.*
***
Best,****
marc****
** **
I am writing to invite you to a seminar on "Semiconductor quantum optical
nanosystems" this Thursday 11:00am in the Grier A room. The speaker will be
Prof. Jonathan Finley of the Technical University Munich, Germany. The
abstract of the talk is attached.
I am looking forward to seeing you there!
Best regards,
Karl Berggren****
*Semiconductor quantum optical nanosystems*
Jonathan Finley****
*Walter Schottky Institut - Centre for Nanotechnology and Nanomaterials*
*TU-München, Am Coulombwall 4a, 85748 Garching, Germany*
In this talk I will give an overview of several research themes pursued in
my group in****
which optically active quantum dots or molecules are embedded within
electrically tunable****
structures and / or tailored photonic environments. For example, we have
used multicolour****
ultrafast pump-probe spectroscopy to investigate charge and spin dynamics
in individual,****
electrically tunable InGaAs quantum dots and molecules. Results show how
the polarization****
state of light can be faithfully mapped onto the exciton spin wavefunction,
manipulated via****
geometric phase control and read out via spin-selective stimulated exciton
emission or****
conditional biexciton absorption. Similar experiments performed on
QD-molecules elucidate****
the comparative roles of elastic and inelastic *intra*-molecular electron
tunneling and allow us****
to directly probe coupling of the molecular exciton to acoustic phonons,
one of the principle****
sources of decoherence. We achieve precise hole spin initialization and
monitor the real time****
coherent evolution of the hole spin wavefunction in an externally applied
magnetic field.****
Dephasing of the exciton and single hole spin wavefunctions is entirely
negligible over****
typical manipulation times (<4ps), facilitating very high fidelity (>97%)
state control.****
Whilst light can be used to control and manipulate to such isolated matter
qubits, photons****
also provide the most attractive route to couple spatially separated
quantum systems. Here,****
technologies based on two-dimensional photonic crystals are attractive
since they allow for****
control of coherent light-matter interactions using defect *nanocavities*,
the efficient routing of****
single photons “on-chip” using *waveguides *that exploit slow light
phenomena and photon****
state characterisation using *beam splitters*. The additional development
of integrated single****
photon detection would open up attractive paradigms for integrated *quantum
optical circuits*.****
With this motivation I will also discuss the use of slow light phenomena in
GaAs photonic****
crystal waveguides to efficiently route single photons and detect them
using *integrated *NbN****
superconducting single photon detectors (SSPDs) on GaAs substrates. Studies
of optimised****
samples reveal that up to 96% of the photons emitted by single dot couple
to the waveguide****
mode and, furthermore, NbN SSPDs on GaAs exhibit remarkable single photon
detection****
efficiencies >20% at 950nm with a timing resolution <90ps. First attempts
to realize****
waveguide coupled SSPDs on GaAs will also be discussed.****
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