12 research outputs found
A highly efficient two level diamond based single photon source
An unexplored diamond defect centre which is found to emit stable single
photons at a measured rate of 1.6 MHz at room temperature is reported. The
novel centre, identified in chemical vapour deposition grown diamond crystals,
exhibits a sharp zero phonon line at 734 nm with a full width at half maximum
of ~ 4 nm. The photon statistics confirm the center is a single emitter and
provides direct evidence of the first true two-level single quantum system in
diamond.Comment: 3 pages, 4 figure
MPCVD processing of titanium-diffused LiNbO3 waveguides: optical characterisation and waveguide restoration
This paper presents some initial findings that explore the material properties of LiNbO3 which has been exposed to a microwave plasma-enhanced chemical vapor deposition (MPCVD) environment. The LiNbO3 was found to undergo a process known as 'reduction' when exposed to this environment. A technique was developed to reverse this process and recover the LiNbO3, which is a crucial first step towards the integration of diamond-based single photon sources with LiNbO3 waveguide technologies
High-performance diamond-based single-photon sources for quantum communication
Quantum communication places stringent requirements on single-photon sources.
Here we report a theoretical study of the cavity Purcell enhancement of two
diamond point defects, the nickel-nitrogen (NE8) and silicon-vacancy (SiV)
centers, for high-performance, near on-demand single-photon generation. By
coupling the centers strongly to high-finesse optical photonic-bandgap cavities
with modest quality factor Q = O(10^4) and small mode volume V = O(\lambda^3),
these system can deliver picosecond single-photon pulses at their zero-phonon
lines with probabilities of 0.954 (NE8) and 0.812 (SiV) under a realistic
optical excitation scheme. The undesirable blinking effect due to transitions
via metastable states can also be suppressed with O(10^{-4}) blinking
probability. We analyze the application of these enhanced centers, including
the previously-studied cavity-enhanced nitrogen-vacancy (NV) center, to
long-distance BB84 quantum key distribution (QKD) in fiber-based, open-air
terrestrial and satellite-ground setups. In this comparative study, we show
that they can deliver performance comparable with decoy state implementation
with weak coherent sources, and are most suitable for open-air communication.Comment: 12 pages, 6 figures, 3 tables, revisions to excitation parameter
Nano-manipulation of diamond-based single photon sources
The ability to manipulate nano-particles at the nano-scale is critical for
the development of active quantum systems. This paper presents a new technique
to manipulate diamond nano-crystals at the nano-scale using a scanning electron
microscope, nano-manipulator and custom tapered optical fibre probes. The
manipulation of a ~ 300 nm diamond crystal, containing a single
nitrogen-vacancy centre, onto the endface of an optical fibre is demonstrated.
The emission properties of the single photon source post manipulation are in
excellent agreement with those observed on the original substrate.Comment: 6 pages, 4 figure
A highly efficient two level diamond based single photon source
An unexplored diamond defect center that is found to emit stable single photons at a measured rate of 1.6 MHz at room temperature is reported. The center, identified in chemical vapor deposition grown diamond crystals, exhibits a sharp zero phonon line at 734 nm with a full width at half maximum of ?4 nm. The photon statistics confirm that the center is a single emitter and provides direct evidence of a true two level single quantum system in diamon
Reactive ion etching of waveguide structures in diamond
Waveguide structures were fabricated in both nanocrystalline CVD diamond (NCD) and HPHT type 1b single crystal diamond using photolithography and reactive ion etching. The combination of these techniques allows the patterning of many long photonic structures simultaneously, making it easily scalable. Emphasis has been placed on reducing sidewall roughness to prevent loss due to scattering. In single crystal diamond a peak-to-peak roughness of approximately 10 nm (estimated from SEM images) was achieved for the majority of the structure sidewall
Diamond single photon sources
We are currently developing a diamond single photon source based on patented technology held at the University of Melbourne. The key technology is the growth of diamond nanocrystals containing single photon sources directly on optical fibre endfaces.1 page(s