141 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
Quantum sensing and imaging with spin defects in hexagonal boron nitride
Color centers in hexagonal boron nitride (hBN) have recently emerged as
promising candidates for a new wave of quantum applications. Thanks to hBN's
high stability and 2-dimensional (2D) layered structure, color centers in hBN
can serve as robust quantum emitters that can be readily integrated into
nanophotonic and plasmonic structures on a chip. More importantly, the recently
discovered optically addressable spin defects in hBN provide a quantum
interface between photons and electron spins for quantum sensing applications.
The most well-studied hBN spin defects, the negatively charged boron vacancy
() spin defects, have been used for quantum sensing of static magnetic
fields, magnetic noise, temperature, strain, nuclear spins, paramagnetic spins
in liquids, RF signals, and beyond. In particular, hBN nanosheets with spin
defects can form van der Waals (vdW) heterostructures with 2D magnetic or other
materials for in situ quantum sensing and imaging. This review summarizes the
rapidly evolving field of nanoscale and microscale quantum sensing with spin
defects in hBN. We introduce basic properties of hBN spin defects, quantum
sensing protocols, and recent experimental demonstrations of quantum sensing
and imaging with hBN spin defects. We also discuss methods to enhance their
sensitivity. Finally, we envision some potential developments and applications
of hBN spin defects.Comment: review article, 21 pages, 13 figure
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
Resonant Excitation of Quantum Emitters in Hexagonal Boron Nitride
Quantum emitters in layered hexagonal boron nitride (hBN) have recently
attracted a great attention as promising single photon sources. In this work,
we demonstrate resonant excitation of a single defect center in hBN, one of the
most important prerequisites for employment of optical sources in quantum
information application. We observe spectral linewidths of hBN emitter narrower
than 1 GHz while the emitter experiences spectral diffusion. Temporal
photoluminescence measurements reveals an average spectral diffusion time of
around 100 ms. On-resonance photon antibunching measurement is also realized.
Our results shed light on the potential use of quantum emitters from hBN in
nanophotonics and quantum information
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