This PDF file contains the front matter associated with SPIE
Proceedings Volume 6903, including the Title Page, Copyright
information, Table of Contents, Introduction (if any), and the
Conference Committee listing.
Fifty years have elapsed since the first concepts in volumetric memories have been put
forward. Nowadays, the perceived need for low cost removable TB/disk storage systems is one more time
fueling the development of 3D media, recording and readout systems. This paper, by reviewing some of the
key historic moments and accomplishments in the development of volumetric recording systems attempts to
shine light on possible future developments and directions while paying a tribute to many of the researchers
that have contributed to the development of this field: in particular to Dr. Hans J. Coufal who for many years
has provided vision, guidance, and leadership by leading recent INSIC Technology Roadmap efforts and
organizing this conference. He is and will be greatly missed at a time when our common dreams may become
a commercial reality.
We study narrowing of nonlinear two photon absorption line shape in system with non-zero permanent dipole moment
difference between the ground- and excited state. The temperature-induced broadening of one photon absorption (1PA)
and two photon absorption (2PA) line shapes is modeled by subjecting the resonance transition frequency to random
fluctuations of varying amplitude and by solving numerically the corresponding two-level density matrix equation of
motion. We show that under conditions, when 1PA and 2PA transitions are both far from saturation, the 2PA
homogeneous line width may be as much as 25% narrower than the corresponding 1PA line width. This offers novel
possibilities for reducing the temperature-induced dephasing in quantum computing, quantum memory and other
applications based on coherent multi-photon interactions.
Rare earth doped thin-films have been produced using laser pulse vapor deposition technique. By changing the thin film growth environment inside the chamber, we were able to create several optical centers. Emission and absorption spectroscopy measurements performed on these structures confirm that that these thinfilms are suitable candidates to be used for ultra-high density spectral storage applications. Scanning electron microscopy studies of these thinfilms were conducted to study degradation in their optical quality upon long-term storage. Results on microscopy show that the deterioration is initiated by nano-gaps and cracks in the capping layer of zinc sulfide.
A recently proposed, photon echo related approach to quantum state storage in atomic ensembles employs
controlled reversible inhomogeneous broadening (CRIB). Beyond storage, a modified version of CRIB promises
controlled quantum state manipulations. As the implementation of CRIB is currently still challenging, we
investigate state transformation based on stimulated photon echoes. Specifically, we show how to translate an all
optical, beamsplitter based setup into a photon echo based setup, and we simulate a photon echo based POVM
(positive operator valued measure) measurement using Maxwell-Bloch equations.
We have recently developed a technique for local, reversible tuning of individual quantum dots on a photonic
crystal chip by up to 1.8nm, which overcomes the problem of large quantum dot inhomogeneous broadening -
usually considered the main obstacle in employing such platform in practical quantum information processing
systems. We have then used this technique to tune single quantum dots into strong coupling with a photonic
crystal cavity, and observed strong coupling both in photoluminescence and in resonant light scattering from the
system, as needed for several proposals for scalable quantum information networks and quantum computation.
A comprehensive theoretical analysis of the cavity quantum electrodynamics (QED) in single-photon Mach-Zehnder
Interferometer (SMZI) based switches and single quantum gates that are intended for the processing of quantum
information encoded in the polarization of single photons inside integrated photonic crystal (PC) quantum networks is
presented. These devices rely on manipulating the geometrical phase of single photons by means of the Single-Photon
Faraday Effect (SPFE), which can be described in terms of a detuned single mode quantum field strongly interacting
with a two-level system or quantum dot (QD) inside nanocavities. The feasibility of such devices depends on the ability
for the field in each arm of the interferometer to couple in their respective nanocavities, successfully interact with the
quantum dot, and when the appropriate phase is accumulated couple out; all these steps being performed with minimum
phase error and losses. Using the Jaynes-Cummings model, the cavity dynamics is studied for various detuning energies
and coupling energies, and it is shown that the design of these devices can achieve low phase error and robustness
against fabrication errors.
Solid state quantum computer hardware may be based on rare-earth-ion-doped crystals. The qubits can
be encoded as nuclear spin states of an ensemble of, e.g., Pr3+ ions, randomly doped into a Y2SiO5 crystal.
Two such qubits can control each other through the dipole blockade effect, and transfers between the two
qubit states can be done at a high fidelity, despite the strongly inhomogeneous nature of the ensemble
approach. In this paper full control over the qubit Bloch sphere is demonstrated, by performing arbitrary
qubit rotations and characterizing the outcomes using quantum state tomography.
We propose two principal schemes of all-optical adders and logical gates based on the dependence of
electromagnetic spectra in photonic bandgap materials containing optically nonlinear layers on the light signal
intensity. The photonic structure behavior with changing intensity is investigated for system consisting of
periodical layered structure covered with optically nonlinear material. The theory of photonic band and local
states dynamics is developed for linear 1D and 2D Si-SiO2 and Ge-Se photonic crystals coated with the nonlinear
doped glass. It is shown that the beam angular-frequency diagrams contain extremely sensitive areas inside the
total reflection range, where the weak nonlinearity leads to dramatic change in light reflection and transmission.
An overview of suitable nonlinear materials and PBG structures is made to evaluate logical device parameters
for different frequencies of laser sources.
Recent developments in the theory of measurement-based quantum computing reduce the problem of building
a quantum computer to that of achieving high quality rotation and measurement of single qubits. The first
generation of such machines may well therefore consist of individual modules each containing a single quantum
system that embodies the qubit. The first demonstrations of entanglement of electronic qubits by measurement
have been performed recently in ion traps. The leading contenders for physical qubits in the solid state are the
negatively charged nitrogen-vacancy defect in diamond and the Stranski Krastanow quantum dot, each of which
offers long electronic spin dephasing times and convenient spin-sensitive optical transitions. In this article we
will compare the strengths and weaknesses of these two systems and discuss some of the challenges to be met in
constructing a measurement based quantum computer in the solid state.
Proposals for quantum computers based on spin degrees of freedom require that individual qubits are placed close
enough so to have a significant exchange interaction between them. We have found theoretically that mixed light-matter
states (polaritons) in planar microcavities can give an extremely long range spin coupling. This implies that spin qubits
can be located several hundreds of nanometers apart while still retaining control on pair interaction through the use of
polaritons. This spin control scheme can be scaled to an array of qubits in a quantum dot lattice. We have theoretically
investigated a lattice of identical quantum dots (or impurity states) coupled to two dimensional photon modes in a planar
cavity. This geometry can be used to design polaritons with novel properties, based on the spatial modulation of the
exciton wave function in the plane of the dots. The application of this structure to the realization of spin-qubit quantum
memories will be discussed.
Scalable quantum information processing using nitrogen-vacancy (NV) centers in diamond will be difficult without
the ability to couple the centers to optical microcavities and waveguides. Here we present our preliminary
result of coupling a single NV center in a nanoparticle to a silica microdisk at cryogenic temperatures. The
cavity-coupled NV photoluminescence is coupled out of the cavity through a tapered fiber. Although the current
system is limited by the spectral properties of the NV center and the Q of the cavity, efficient particle-cavity
and cavity-waveguide coupling should lead to the realization of a "one-dimensional atom" as needed for CQED,
enable single-shot electron-spin readout, and increase the probability of success in entanglement schemes based
on single-photon detection.
Spin g-factors and lifetimes were studied with picosecond pump-probe techniques for a set of samples of InAs quantum
dots of uniform height. The samples were grown by MBE with a cap and flush sequence to produce a height of 2.5 nm.
Remote doping provided electrons in the dots. Electron coherence was excited by a fast pump pulse and detected
through the Faraday rotation of a probe pulse. The results show an in plane g-factor of 0.427 and lifetimes around 1 ns
that shorten for increasing magnetic fields. For an undoped sample, signals from singly charged and neutral dots are
observed and simulated to provide the hole g-factor and parameters for the neutral exciton. The undoped sample also
exhibits signals for negative delays attributed to mode-locking of the spin coherence to the optical pulse train. This
observation indicates that the true spin coherence lasts at least 12 ns.
The exact wave function and asymptotic expressions for the system state vectors under strong initial coherent
fields are found in the work for the two-atom models with nondegenerate two-photon interaction and nondegen-
erate Raman interaction. The atom-field entanglement is considered via linear entropy criterion. The system
revivals to unentangled states are shown to appear for both models. The disentanglement times are derived in
the work. The atom-atom entanglement induced by thermal noise is investigated for the both models.