3 June 2010, Cambridge, UK
• First simple, voltage powered device for producing entangled light
• Breakthrough could lead to semiconductor chips for quantum computing
Fifty years after the discovery of the laser, scientists in Cambridge have invented
a novel type of light source, which could again revolutionise data processing, communications
and storage applications. The Entangled Light Emitting Diode, which is the result
of collaboration between Toshiba Research Europe Limited and the Cavendish Laboratory
of the University of Cambridge, will be reported today in the scientific journal
Nature.
Dr Andrew Shields, who directs this work at Toshiba Research Europe, commented,
“Although entangled light has been produced previously by shining an intense laser
beam on crystals, the new simple device is the first voltage-powered source. The
discovery is significant because it will allow electrical addressing of many entangled
light emitters on a single chip, opening the path to ultra-powerful semiconductor
processors based on quantum computation.”
The new light source is based upon similar semiconductor Light Emitting Diode technology
to that used in computer indicator lamps, traffic lights and modern household lighting
and so is suitable for mass manufacture. It could therefore allow compact, cheap
entangled emitters to be produced in the future and thus enable new applications
that exploit the quantum properties of light.
In contrast to conventional LEDs, the entangled LED contains a tiny nanometer-scale
region of semiconductor, called a quantum dot, which converts electrical current
into entangled light. Dr Mark Stevenson, Senior Research Scientist on the project,
explained, “For successful operation it was essential to optimise the thickness
of the semiconductor material surrounding the quantum dot to control the supply
of current to the dot. In addition the properties of the dot itself had to be carefully
tailored to produce entangled emission.”
Entangled light is a key ingredient in a quantum computer, a machine with massive
processing power that will be able to solve problems that are virtually intractable
otherwise, such as modelling new pharmaceuticals or materials. Other applications
of entangled light include extending the range of secure communication systems based
on quantum cryptography and increasing the storage capacity of optical disks.
About Toshiba
Toshiba is a world leader and innovator in pioneering high technology, a diversified
manufacturer and marketer of advanced electronic and electrical products spanning
information & communications systems; digital consumer products; electronic devices
and components; power systems, including nuclear energy; industrial and social infrastructure
systems; and home appliances.
Toshiba was founded in 1875, and today operates a global network of more than 740
companies, with 204,000 employees worldwide and annual sales surpassing 6.3 trillion
yen (US$68 billion). Visit Toshiba's web site at
www.toshiba.co.jp/index.htm.
About Toshiba Research Europe Ltd
Toshiba Corporation is fully committed to the research and development of future
technologies. This commitment has resulted in Toshiba having a record number of
world firsts, including the first laptop PC (1985), the first single chip MPEG4
videophone LSI (1998) and the first DVD player (Oct. 1996). Over the 3 years to
end March 2010, the Corporation anticipates a total global R&D expenditure of JPY1,290bn.
Toshiba Corporation established its first overseas research centre in 1991, with
the opening of Toshiba Cambridge Research Centre Ltd in the UK. This was renamed
Toshiba Research Europe Ltd (TREL) in August 1998, when a new telecommunications
laboratory in Bristol was launched. TREL now has two research laboratories in the
UK; the Cambridge Research Laboratory (CRL) in Cambridge, and Telecommunications
Research Laboratory (TRL) in Bristol.
Further Information:
Entangled-Light-Emittting Diode
Associated publication:
C L Salter
et al., Nature, 465, 594–597 (2010)
