An Optical Switch Based On a Single Nano-Diamond
Oct. 15, 2013 — A recent
study led by researchers of the ICFO (Institute of Photonic Sciences)
demonstrates that a single nano-diamond can be operated as an ultrafast
single-emitter optical switch operating at room temperature.
Artist's illustration showing the nanomanipulation of an artificial atom. (Credit: ICFO)
The scientific results of this study have been published in Nature Physics.
Electronic transistors have become a key component to modern
electronics, drastically improving the speed of information processing
of current technologies. An electronic transistor is a semiconductor
device used to amplify and switch electronic signals. The much sought
after optical transistor (the photonic counterpart of the electronic
transistor) is poised to become a central ingredient in the development
of optical signal processing. The motivation for using photons rather
than electrons not only comes from their faster dynamics but also from
their weaker interaction with the environment, which enable a high
degree of integration and the realization of quantum operations.
Prior studies have demonstrated that single dye molecules can be
operated as optical transistors with the disadvantage that they worked
exclusively at extremely low temperatures. Such restrictions on the
temperature made these optical transistors cumbersome for application to
quantum computing.
However in this recent ICFO study, scientists have shown that a
nano-size diamond at room temperature can act as an efficient optical
switch controllable with light. A Nano-diamond containing a nitrogen
impurity behaves like an artificial atom although much more stable at
room temperature than a real atom due to its encapsulation. The ICFO
scientists discovered a novel physical mechanism that enables the
control of the way the nano-diamond interacts with light. While excited
to its ON state by a green laser, a suitable near infrared illumination
was found to act as an efficient and fast way to switch it OFF. Based on
this simple concept, they were able to modulate the optical
nano-diamond ON and OFF at extremely high speeds, demonstrating its
robustness and viability for very fast information processing and
quantum computer operations.
Quidant remarks that "what is really attractive about our discovery
is that our nano-switch combines very small dimensions (compatible with
integrating a large number of them in a small area) with very fast
response time (meaning lots of operations in a short time) and operation
at room temperature."
This new technique will contribute to the development of future
integrated optical circuits as well as quantum information processing
for quantum computing.
This work is a collaborative effort between the research groups at
ICFO led by ICREA Professors at ICFO Javier GarcĂa de Abajo and Romain
Quidant.
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