16 research outputs found
Optical sensing with Anderson-localised light
We show that fabrication imperfections in silicon nitride photonic crystal
waveguides can be used as a resource to efficiently confine light in the
Anderson-localised regime and add functionalities to photonic devices. Our
results prove that disorder-induced localisation of light can be utilised to
realise an alternative class of high-quality optical sensors operating at room
temperature. We measure wavelength shifts of optical resonances as large as
15.2 nm, more than 100 times the spectral linewidth of 0.15\,nm, for a
refractive index change of about 0.38. By studying the temperature dependence
of the optical properties of the system, we report wavelength shifts of up to
about 2 nm and increases of more than a factor 2 in the quality factor of the
cavity resonances, when going from room to cryogenic temperatures. Such a
device can allow simultaneous sensing of both local contaminants and
temperature variations, monitored by tens of optical resonances spontaneously
appearing along a single photonic crystal waveguide. Our findings demonstrate
the potential of Anderson-localised light in photonic crystals for scalable and
efficient optical sensors operating in the visible and near-infrared range of
wavelengths.Comment: 10 pages, 3 figure
Metallic nanorings for broadband, enhanced extraction of light from solid-state emitters
We report on the increased extraction of light emitted by solid-state sources
embedded within high refractive index materials. This is achieved by making use
of a local lensing effect by sub-micron metallic rings deposited on the sample
surface and centered around single emitters. We show enhancements in the
intensity of the light emitted by InAs/GaAs single quantum dot lines into free
space as high as a factor 20. Such a device is intrinsically broadband and
therefore compatible with any kind of solid-state light source. We foresee the
fabrication of metallic rings via scalable techniques, like nano-imprint, and
their implementation to improve the emission of classical and quantum light
from solid-state sources. Furthermore, while increasing the brightness of the
devices, the metallic rings can also act as top contacts for the local
application of electric fields for carrier injection or wavelength tuning.Comment: 10 pages, 3 figure
Quantum communication networks with defects in silicon carbide
Quantum communication promises unprecedented communication capabilities
enabled by the transmission of quantum states of light. However, current
implementations face severe limitations in communication distance due to photon
loss. Silicon carbide (SiC) defects have emerged as a promising quantum device
platform, offering strong optical transitions, long spin coherence lifetimes
and the opportunity for integration with semiconductor devices. Some defects
with optical transitions in the telecom range have been identified, allowing to
interface with fiber networks without the need for wavelength conversion. These
unique properties make SiC an attractive platform for the implementation of
quantum nodes for quantum communication networks. We provide an overview of the
most prominent defects in SiC and their implementation in spin-photon
interfaces. Furthermore, we model a memory-enhanced quantum communication
protocol in order to extract the parameters required to surpass a direct
point-to-point link performance. Based on these insights, we summarize the key
steps required towards the deployment of SiC devices in large-scale quantum
communication networks.Comment: 20 pages, 8 figure