36 research outputs found
Coupling of Nitrogen-Vacancy Centers to Photonic Crystal Cavities in Monocrystalline Diamond
The zero-phonon transition rate of a nitrogen-vacancy center is enhanced by a
factor of ~70 by coupling to a photonic crystal resonator fabricated in
monocrystalline diamond using standard semiconductor fabrication techniques.
Photon correlation measurements on the spectrally filtered zero-phonon line
show antibunching, a signature that the collected photoluminescence is emitted
primarily by a single nitrogen-vacancy center. The linewidth of the coupled
nitrogen-vacancy center and the spectral diffusion are characterized using
high-resolution photoluminescence and photoluminescence excitation
spectroscopy
Towards Integrated Optical Quantum Networks in Diamond
We demonstrate coupling between the zero phonon line (ZPL) of nitrogen-vacancy centers in diamond and the modes of optical micro-resonators fabricated in single crystal diamond membranes sitting on a silicon dioxide substrate. A more than ten-fold enhancement of the ZPL is estimated by measuring the modification of the spontaneous emission lifetime. The cavity-coupled ZPL emission was further coupled into on-chip waveguides thus demonstrating the potential to build optical quantum networks in this diamond on insulator platform
Millisecond spin-flip times of donor-bound electrons in GaAs
We observe millisecond spin-flip relaxation times of donor-bound electrons in
high-purity n-GaAs . This is three orders of magnitude larger than previously
reported lifetimes in n-GaAs . Spin-flip times are measured as a function of
magnetic field and exhibit a strong power-law dependence for fields greater
than 4 T . This result is in qualitative agreement with previously reported
theory and measurements of electrons in quantum dots.Comment: 4 pages, 4 figure
Modification of the spontaneous emission rate of nitrogen-vacancy centers in diamond by coupling to plasmons
Nitrogen-vacancy centers in diamond are widely studied both as a testbed for solid state quantum optics and for their applications in quantum information processing and magnetometry. Here we demonstrate coupling of the nitrogen-vacancy centers to gap plasmons in metal nano-slits. We use diamond samples where nitrogen-vacancy centers are implanted tens of nanometers under the surface. Silver nano-slits are patterned on the sample such that diamond ridges tens of nanometers wide fill the slit gap. We measure enhancement of the spontaneous emission rate of the zero photon line by a factor of 3 at a temperature of 8K
Observation of the dynamic Jahn-Teller effect in the excited states of nitrogen-vacancy centers in diamond
The optical transition linewidth and emission polarization of single
nitrogen-vacancy (NV) centers are measured from 5 K to room temperature.
Inter-excited state population relaxation is shown to broaden the zero-phonon
line and both the relaxation and linewidth are found to follow a T^5 dependence
for T up to 100 K. This dependence indicates that the dynamic Jahn-Teller
effect is the dominant dephasing mechanism for the NV optical transitions at
low temperatures
Time-resolved spectroscopy of multi-excitonic decay in an InAs quantum dot
The multi-excitonic decay process in a single InAs quantum dot is studied
through high-resolution time-resolved spectroscopy. A cascaded emission
sequence involving three spectral lines is seen that is described well over a
wide range of pump powers by a simple model. The measured biexcitonic decay
rate is about 1.5 times the single-exciton decay rate. This ratio suggests the
presence of selection rules, as well as a significant effect of the Coulomb
interaction on the biexcitonic wavefunction.Comment: one typo fixe
Sub-microsecond correlations in photoluminescence from InAs quantum dots
Photon correlation measurements reveal memory effects in the optical emission
of single InAs quantum dots with timescales from 10 to 800 ns. With above-band
optical excitation, a long-timescale negative correlation (antibunching) is
observed, while with quasi-resonant excitation, a positive correlation
(blinking) is observed. A simple model based on long-lived charged states is
presented that approximately explains the observed behavior, providing insight
into the excitation process. Such memory effects can limit the internal
efficiency of light emitters based on single quantum dots, and could also be
problematic for proposed quantum-computation schemes.Comment: 8 pages, 8 figure