28 research outputs found
A Diffraction Limited Fabry-Perot Cavity with a Strongly Focused Mode
Ph.DDOCTOR OF PHILOSOPH
Diffraction-limited Fabry-Perot Cavity in the Near Concentric Regime
Nearly concentric optical cavities can be used to prepare optical fields with
a very small mode volume. We implement an anaclastic design of a such a cavity
that significantly simplifies mode matching to the fundamental cavity mode. The
cavity is shown to have diffraction-limited performance for a mode volume of
. This is in sharp contrast with the behavior of cavities
with plano-concave mirrors, where aberrations significantly increase the losses
in the fundamental mode. We estimate the related cavity QED parameters and show
that the proposed cavity design allows for strong coupling without a need for
high finesse or small physical cavity volume.Comment: 6 pages, 7 figure
The photon pair source that survived a rocket explosion
We report on the performance of a compact photon pair source that was
recovered intact from a failed space launch. The source had been embedded in a
nanosatellite and was designed to perform pathfinder experiments leading to
global quantum communication networks using spacecraft. Despite the launch
vehicle explosion soon after takeoff?, the nanosatellite was successfully
retrieved from the accident site and the source within it was found to be fully
operational. We describe the assembly technique for the rugged source.
Post-recovery data is compared to baseline measurements collected before the
launch attempt and no degradation in brightness or polarization correlation was
observed. The survival of the source through an extreme environment provides
strong evidence that it is possible to engineer rugged quantum optical systems
Noise-Tolerant Object Detection and Ranging Using Quantum Correlations
Imaging, detection and ranging of objects in the presence of significant
background noise is a fundamental challenge in optical sensing. Overcoming the
limitations imposed in conventional methods, quantum light sources show higher
resistance against noise in a time-correlation-based quantum illumination.
Here, we introduce the advantage of using not only time correlations but also
polarization correlations in photon pairs in the detection of an object that is
embedded in a noisy background. In this direction, a time- and
polarization-correlated photon pair source using the spontaneous parametric
down-conversion process is exploited. We found that the joint measurement of
correlated pairs allows distinguishing the signal from the noise photons and
that leads to an improved signal-to-noise ratio. Our comparative study revealed
that using polarization correlations in addition to time correlations provides
improved noise rejection. Furthermore, we show that polarization correlation
allows undoing the detector limitation where high background often leads to
detector saturation.Comment: The file is 7 pages of double columns data and contains 6 figure
Deploying quantum light sources on nanosatellites II: lessons and perspectives on CubeSat spacecraft
To enable space-based quantum key distribution proposals the Centre for
Quantum Technologies is developing a source of entangled photons ruggedized to
survive deployment in space and greatly miniaturised so that it conforms to the
strict form factor and power requirements of a 1U CubeSat. The Small Photon
Entangling Quantum System is an integrated instrument where the pump, photon
pair source and detectors are combined within a single optical tray and
electronics package that is no larger than 10 cm x 10 cm x 3 cm. This footprint
enables the instrument to be placed onboard nanosatellites or the CubeLab
structure aboard the International Space Station. We will discuss the
challenges and future prospects of CubeSat-based missions.Comment: Submitted to SPIE Quantum Information Science and Technology. Paper
number 9648-4