We demonstrate that the emission spectrum from a quantum dot near the edge of a photonic band gap (PBG) can be
spectrally resolved on the subwavelength scale using coherent control. In the case of the coherent control, confined light
near a quantum dot embedded in photonic crystals can be released by changing the phase of the external laser phase,
without closing the PBG. Moreover, in this demonstration, we examine the spectrum resolution of the coherent control,
which indicates that the spectrum resolution is the subwavelength scale. Therefore, even if there are many quantum dots
are embedded in photonic crystals, we can be operated a quantum dot with a specific resonant frequency. This technique
may provide a basis for N-qubit operation for quantum computations and nanophotonic devices.
We have demonstrated the coherent control of nanoscale objects (such as quantum dots) embedded in photonic crystals, which provides a basis for a one-qubit phase rotation gate that is one of the universal quantum logic gates for quantum information processing. In this demonstration, the quantum electrodynamics of the atomic system is calculated by the Schrödinger equation. Using the results of the calculation, the quantum electrodynamics is graphically represented by a Bloch sphere. This shows that the quantum state is rotated on the Bloch sphere, and this rotation is stopped or started, depending on the laser phase, which can act as a one-qubit phase rotation gate.
We have demonstrated the coherent control of photonic bandgap (PBG) devices composed of a three-level atom
embedded in three-dimensional PBG structures, which enables us to strongly suppress the loss of quantum information
not only during its storage but also during its processing. We find that this ultralow-loss optical quantum information
processing can be realized by generating the upper atomic level splitting inside the PBG and by tuning one of the split
levels to a dark line in the emission spectrum (zeros in the spectrum at certain values of the emitted photon frequency).
Furthermore, we show that the coherent control may provide a basis for the universal quantum logic gate operation in
quantum computing.
We demonstrate the coherent control of the excited states of the atom embedded in a photonic band gap (PBG) structure by means of a Rabi oscillation. In this demonstration, we show that the atomic decay is strongly suppressed not only during the Rabi oscillation but also during switching process to the final steady state. This switching is achieved by eliminating one of localized field modes arising from the localization of the emitted photon in the vicinity of the atom due to the PBG, where the suppression of the atomic decay during the switching is facilitated by achieving this elimination not outside the PBG but inside the PBG. Such a coherent control of excited states without the atomic decay suggests the possibility of extending the atomic system for quantum computing to act as nearly lossless.
We demonstrate optical encoding in an atomic device, considered as a key component in quantum computers. The atomic device consists of a three-level atom embedded in photonic crystals witout external driving lasers. We find that a large amount of population trapping in the upper levels of the atom can be achieved, which is relevant for a strong optical memory effect. Furthermore, the trapped populations keep a memory of the initial atomic state including two-state quantum information, so that the atomic device can be used for a quantum bit encoding the quantum information.
In real photonic band gap (PBG) materials, the PBG is highly anisotropic. In this paper, we propose an optical memory composed of a three-level atom embedded in the realistic anisotropic PBG structures without external driving lasers, which can be considered as essential components for a novel class of computation including an optical quantum computation.
We propose all-optical switching schemes using a single three-level atomic system placed within a 3D photonic crystal that exhibits a complete 3D photonic band gap. The optical schemes we propose can be classified into two types with respect to a physical process that causes the switching effect. One switching type is mediated by changing an atom-field coupling strength. The other switching type is mediated by controlling quantum interference. Furthermore, we consider conditions of realizing a wide range of signals, which contributes to an improvement of the Signal to Noise ratio. The phases and strengths of the external laser fields required for the all-optical switching are revealed. Next, we estimate their switching times. Using these results, we propose the fastest scheme for every configuration of the atomic system, which is important for realizing a high-speed optical memory or switching device on an atomic scale that can be used in novel optical integrated systems, such as quantum computers.
In this study, we examine the switching time of photonic memory devices, which we calculate for several switching schemes. Using the numerical results, we find that the switching scheme in which the switching is mediated by applying a small dc field to the device is the fastest one.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.