'The researchers
show photoluminescence from an optically levitated nano diamond.
Photo by J. Adam
Fenster/University of Rochester. '
(August 12, 2015) Researchers
at the University of Rochester have measured for the first time light emitted
by photoluminescence from a nanodiamond levitating in free space. In a paper
published this week in Optics Letters, they describe how they used a laser to
trap nanodiamonds in space, and – using another laser – caused the diamonds to
emit light at given frequencies.
The experiment, led by Nick Vamivakas, an assistant
professor of optics, demonstrates that it is possible to levitate diamonds as
small as 100 nanometers (approximately one-thousandth the diameter of a human
hair) in free space, by using a technique known as laser trapping.
"Now that we have shown we can levitate nanodiamonds
and measure photoluminescence from defects inside the diamonds, we can start
considering systems that could have applications in the field of quantum
information and computing," said Vamivakas. He said an example of such a
system would be an optomechanical resonator.
Vamivakas explained that optomechanical resonators are
structures in which the vibrations of the system, in this case the trapped
nanodiamond, can be controlled by light. "We are yet to explore this, but
in theory we could encode information in the vibrations of the diamonds and
extract it using the light they emit."
Possible avenues of interest in the long-term with these
nano-optomechanical resonators include the creation of what are known as
Schrödinger Cat states (macroscopic, or large-scale, systems that are in two
quantum states at once). These resonators could also be used as extremely
sensitive sensors of forces – for example, to measure tiny displacements in the
positions of metal plates or mirrors in configurations used in microchips and
understand friction better on the nanoscale.
Nick Vamivakas and
Levi Neukirch in front of their experiment.
Photo by J. Adam
Fenster / University of Rochester
"Levitating particles such as these could have
advantages over other optomechanical oscillators that exist, as they are not
attached to any large structures," Vamivakas explained. "This would
mean they are easier to keep cool and it is expected that fragile quantum
coherence, essential for these systems to work, will last sufficiently long for
experiments to be performed."