New technique introducing foreign atoms in optical trapping allows greater manipulation of nanoparticles

November 15, 2016, Macquarie University

Macquarie University researchers have demonstrated a new technique exploiting the presence of foreign atoms within a diamond crystal, using light to affect the motion of the entire nanoparticle – opening the door to applying powerful quantum technologies to the manipulation of ultrasmall nanoparticles and an unprecedented degree of control at the nanoscale.

The research, published in Nature Physics, measured the force on nanoscale diamond crystals (which are as small as one thousandth of the breadth of a human hair) that were immersed in water and optically trapped by a tightly focused laser beam-optical tweezers.

Dr Thomas Volz and colleagues from the Department of Physics and Astronomy and the ARC Centre of Excellence on Engineered Quantum Systems (EQuS), found that when tracking the motion of the individual nanodiamonds in the optical tweezers, the had a significant influence on the nanocrystal motion. This is remarkable, especially considering that only a few of these foreign atoms actually interact with the near-resonant laser light.

"Usually, the light in the optical tweezers interacts with the nanoparticle itself. In this study however a group of special foreign atoms were introduced in the diamond nanoparticle. When the laser light is chosen close to the transition of these foreign 'special' atoms, the motion of the whole crystal is affected, despite there being only about 10,000 of these atoms within a crystal made of about 100 million carbons," said Dr Volz.

"These near-resonant forces are typically known from the manipulation of single atoms by light but not in the case of nanomanipulation. This research demonstrates for the first time the effect of these forces in the context of nanomanipulation. Even more interestingly, these forces are only measurable because of a unique effect which is seldom observed in nature: a cooperative interaction of the foreign atoms amongst each other. Only by these atoms acting together in a cooperative way can we see their effect," said first author Dr Mathieu Juan.

"Our research is motivated by the possibility to pioneer a technique well known from atom manipulation in the field of nanoparticle manipulation (in a liquid environment). The technique is powerful, and one can think of engineering nanodiamonds with different types of foreign atoms to make their effect even stronger and ultimately trap nanoparticles as small as a few nanometres in diameter while systematically moving them around in cells," said Dr Volz.

"The forces we observed have not been seen before and with these exciting possibilities at hand, this research could lead to a new type of optical tweezers being developed, which will have applications across different fields. Beyond applications in biology and medicine where near-resonant could be used for bio-imaging and drug delivery, this research could impact the fields of quantum nanotechnology and sensing," said Dr Carlo Bradac, joint first author.

Explore further: Elucidating energy shifts in optical tweezers

More information: Mathieu L. Juan et al. Cooperatively enhanced dipole forces from artificial atoms in trapped nanodiamonds, Nature Physics (2016). DOI: 10.1038/nphys3940

Related Stories

Elucidating energy shifts in optical tweezers

May 8, 2013

A small piece of paper sticks to an electrically charged plastic ruler. The principle of this simple classroom physics experiment is applied at the microscopic scale by so-called optical tweezers to get the likes of polystyrene ...

Scientists set traps for atoms with single-particle precision

November 3, 2016

Atoms, photons, and other quantum particles are often capricious and finicky by nature; very rarely at a standstill, they often collide with others of their kind. But if such particles can be individually corralled and controlled ...

Trapping single atoms in a uniform fashion

September 28, 2016

Single neutral atoms trapped individually in optical microtraps are incredibly useful tools for studying quantum physics, as the atoms then exist in complete isolation from the environment. Arrays of optical microtraps containing ...

Physicists create nanoscale mirror with only 2000 atoms

September 26, 2016

Mirrors are the simplest means to manipulate light propagation. Usually, a mirror is a macroscopic object composed of a very large number of atoms. In the September 23th issue of the Physical Review Letters, Prof. Julien ...

Cooling with the coldest matter in the world

November 24, 2014

Physicists at the University of Basel have developed a new cooling technique for mechanical quantum systems. Using an ultracold atomic gas, the vibrations of a membrane were cooled down to less than 1 degree above absolute ...

A little light interaction leaves quantum physicists beaming

August 24, 2015

A team of physicists at the University of Toronto (U of T) have taken a step toward making the essential building block of quantum computers out of pure light. Their advance, described in a paper published this week in Nature ...

Recommended for you

Compelling evidence for small drops of perfect fluid

December 10, 2018

Nuclear physicists analyzing data from the PHENIX detector at the Relativistic Heavy Ion Collider (RHIC)—a U.S. Department of Energy (DOE) Office of Science user facility for nuclear physics research at Brookhaven National ...

Engineers invent groundbreaking spin-based memory device

December 7, 2018

A team of international researchers led by engineers from the National University of Singapore (NUS) have invented a new magnetic device to manipulate digital information 20 times more efficiently and with 10 times more stability ...

Multichannel vectorial holographic display and encryption

December 7, 2018

Holography is a powerful tool that can reconstruct wavefronts of light and combine the fundamental wave properties of amplitude, phase, polarization, wave vector and frequency. Smart multiplexing techniques (multiple signal ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.