114 research outputs found
Suppression of Spectral Diffusion by Anti-Stokes Excitation of Quantum Emitters in Hexagonal Boron Nitride
Solid-state quantum emitters are garnering a lot of attention due to their
role in scalable quantum photonics. A notable majority of these emitters,
however, exhibit spectral diffusion due to local, fluctuating electromagnetic
fields. In this work, we demonstrate efficient Anti-Stokes (AS) excitation of
quantum emitters in hexagonal boron nitride (hBN), and show that the process
results in the suppression of a specific mechanism responsible for spectral
diffusion of the emitters. We also demonstrate an all-optical gating scheme
that exploits Stokes and Anti-Stokes excitation to manipulate spectral
diffusion so as to switch and lock the emission energy of the photon source. In
this scheme, reversible spectral jumps are deliberately enabled by pumping the
emitter with high energy (Stokes) excitation; AS excitation is then used to
lock the system into a fixed state characterized by a fixed emission energy.
Our results provide important insights into the photophysical properties of
quantum emitters in hBN, and introduce a new strategy for controlling the
emission wavelength of quantum emitters
Monolithic Integration of Single Quantum Emitters in hBN Bullseye Cavities
The ability of hexagonal boron nitride to host quantum emitters in the form
of deep-level color centers makes it an important material for quantum photonic
applications. This work utilizes a monolithic circular Bragg grating device to
enhance the collection of single photons with 436 nm wavelength emitted from
quantum emitters in hexagonal boron nitride. We observe a 6- fold increase in
collected intensity for a single photon emitter coupled to a device compared to
an uncoupled emitter, and show exceptional spectral stability at cryogenic
temperature. The devices were fabricated using a number of etching methods,
beyond standard fluorine-based reactive ion etching, and the quantum emitters
were created using a site-specific electron beam irradiation technique. Our
work demonstrates the potential of monolithically-integrated systems for
deterministically-placed quantum emitters using a variety of fabrication
options
Facile Self-Assembly of Quantum Plasmonic Circuit Components
Efficient coupling between solid state quantum emitters and plasmonic
waveguides is important for the realization of integrated circuits for quantum
information, communication and sensing. However, realization of plasmonic
circuits is still scarce, particularly due to challenges associated with
accurate positioning of quantum emitters near plasmonic resonators. Current
pathways for the construction of plasmonic circuits involve cumbersome and
costly methods such as scanning atomic force microscopy or mechanical
manipulation, where individual elements are physically relocated using the
scanning tip. Here, we introduce a simple, fast and cost effective chemical
self-assembly method for the attachment of two primary components of a
practical plasmonic circuit: a single photon emitter and a waveguide. Our
method enables coupling of nanodiamonds with a single quantum emitter (the
nitrogen-vacancy (NV) center) onto the terminal of a silver nanowire, by simply
varying the concentration of ascorbic acid (AA) in a reaction solution. The AA
concentration is used to control the extent of agglomeration, and can be
optimised so as to cause preferential, selective activation of the tips of the
nanowires. The nanowire-nanodiamond structures show efficient plasmonic
coupling of fluorescence emission from single NV centers into surface plasmon
polariton (SPP) modes, evidenced by a more than two-fold reduction in
fluorescence lifetime and an increase in fluorescence intensity.Comment: Published in Advanced Materials on 2 June 201
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