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Primeur weekly 2014-05-26

Special

The N4S Programme is building new infrastructure for industrial software applications ...

The Sprint-model in large projects ...

Interview with David Wallom about the launch of the Federated Cloud as a production service ...

David Wallom to recommend the EGI Federated Cloud as a production IaaS infrastructure for the European Economic Area ...

The Cloud

Fujitsu enhances suite of private Cloud platform products with support for OpenStack ...

Oracle Managed Cloud Services earns elite status for federal deployments ...

SoftLayer helps Mankind Pharma drive business growth ...

EuroFlash

Bull aims at delivering operational excellence for IT Departments ...

Computer models helping unravel the science of life? ...

Improved computer simulations enable better calculation of interfacial tension ...

Atos to acquire Bull to create a European global leader in Cloud, Cybersecurity, and Big Data ...

USFlash

TDC provides core video expertise for largest-ever light festival Vivid Sydney ...

Scientists study biomechanics behind amazing ant strength ...

The University of Tsukuba in Japan puts additional Cray CS300 cluster supercomputer into production ...

Mellanox collaborates with DataON to provide Cluster-in-a-Box storage appliance ...

Supermicro announces storage solutions optimized for extreme scale-out object-storage applications ...

Don't blink: NIST studies why quantum dots suffer from 'fluorescence intermittency' ...

Red Hat delivers powerful new capabilities in OpenShift Enterprise 2.1 ...

Inventors of Analytics System forerunner inducted into National Inventors Hall of Fame ...

UChicago to lead quantum engineering research team ...

New analysis eliminates a potential speed bump in quantum computing ...

Advance brings 'hyperbolic metamaterials' closer to reality ...

NIWA supercomputer back on-line ...

Don't blink: NIST studies why quantum dots suffer from 'fluorescence intermittency'

22 May 2014 Gaithersburg - Researchers at the National Institute of Standards and Technology (NIST), working in collaboration with the Naval Research Laboratory, have found that a particular species of quantum dots that weren't commonly thought to blink, do. So what? Well, although the blinks are short - on the order of nanoseconds to milliseconds - even brief fluctuations can result in efficiency losses that could cause trouble for using quantum dots to generate photons that move information around inside a quantum computer or between nodes of a future high-security internet based on quantum telecommunications.

Beyond demonstrating that the dots are blinking, the team also suggests a possible culprit.

Scientists have regarded indium arsenide and gallium arsenide (InAs/GaAs) quantum dots to be promising as single photon sources foruse in different future computing and communication systems based on quantum technologies. Compared to other systems, researchers have preferred these quantum dots because they appeared to not blink and because they can be fabricated directly into the types of semiconductor opto-electronics that have been developing over the past few decades.

The NIST research team also thought these quantum dots were emitting steady light perfectly, until they came upon one that was obviously blinking - or was "fluorescently intermittent", in technical terms. They decided to see if they could find others that were blinking in a less obvious way.

While most previous experiments surveyed the dots in bulk, the team tested these dots as they would be used in an actual device. Using an extremely sensitive photon autocorrelation technique to uncover subtle signatures of blinking, they found that the dots blink over timescales ranging from tens of nanoseconds to hundreds of milliseconds. Their results suggest that building photonic structures around the quantum dots - something you'd have to do to make many applications viable - may make them significantly less stable as a light source.

"Most of the previous experimental studies of blinking inInAs/GaAs quantum dots looked at their behaviour after the dots have been grown but before the surrounding devices have been fabricated", stated Kartik Srinivasan, one of the authors of the study. "However, there is no guarantee that a quantum dot will remain non-blinking after the nanofabrication of a surrounding structure, which introduces surfaces and potential defects within 100 nanometers of the quantum dot. We estimate the radiative efficiency of the quantum dots to be between about 50 and 80 percent after the photonic structures are fabricated, significantly less than the 100 percent efficiency that future applications will require."

According to Marcelo Davanço, another author of the study, future work will focus on measuring dots both before and after device fabrication to better assess whether the fabrication is indeed a source of the defects thought to cause the blinking. Ultimately, the authors hope to understand what types of device geometries will avoid blinking while still efficiently funneling the emitted photons into a useful transmission channel, such as an optical fiber.

M. Davanço, C. Stephen Hellberg, S. Ates, A. Badolato and K. Srinivasan are the authors of "Multiple time scale blinking in InAs quantum dot single-photon sources". The paper appears inPhys. Rev. B89, 161303(R) and was published on 16 April 2014.
Source: National Institute of Standards and Technology - NIST

Back to Table of contents

Primeur weekly 2014-05-26

Special

The N4S Programme is building new infrastructure for industrial software applications ...

The Sprint-model in large projects ...

Interview with David Wallom about the launch of the Federated Cloud as a production service ...

David Wallom to recommend the EGI Federated Cloud as a production IaaS infrastructure for the European Economic Area ...

The Cloud

Fujitsu enhances suite of private Cloud platform products with support for OpenStack ...

Oracle Managed Cloud Services earns elite status for federal deployments ...

SoftLayer helps Mankind Pharma drive business growth ...

EuroFlash

Bull aims at delivering operational excellence for IT Departments ...

Computer models helping unravel the science of life? ...

Improved computer simulations enable better calculation of interfacial tension ...

Atos to acquire Bull to create a European global leader in Cloud, Cybersecurity, and Big Data ...

USFlash

TDC provides core video expertise for largest-ever light festival Vivid Sydney ...

Scientists study biomechanics behind amazing ant strength ...

The University of Tsukuba in Japan puts additional Cray CS300 cluster supercomputer into production ...

Mellanox collaborates with DataON to provide Cluster-in-a-Box storage appliance ...

Supermicro announces storage solutions optimized for extreme scale-out object-storage applications ...

Don't blink: NIST studies why quantum dots suffer from 'fluorescence intermittency' ...

Red Hat delivers powerful new capabilities in OpenShift Enterprise 2.1 ...

Inventors of Analytics System forerunner inducted into National Inventors Hall of Fame ...

UChicago to lead quantum engineering research team ...

New analysis eliminates a potential speed bump in quantum computing ...

Advance brings 'hyperbolic metamaterials' closer to reality ...

NIWA supercomputer back on-line ...