Featured Research

from universities, journals, and other organizations

Lasers used to form 3-D crystals made of nanoparticles

Date:
June 3, 2011
Source:
University of Michigan
Summary:
Physicists have used the electric fields generated by intersecting laser beams to trap and manipulate thousands of microscopic plastic spheres, thereby creating 3-D arrays of optically induced crystals.

Still image of a video showing microscope images of the crystals forming.
Credit: From a video provided by Georg Raithel, University of Michigan

University of Michigan physicists used the electric fields generated by intersecting laser beams to trap and manipulate thousands of microscopic plastic spheres, thereby creating 3-D arrays of optically induced crystals.

The technique could someday be used to analyze the structure of materials of biological interest, including bacteria, viruses and proteins, said U-M physicist Georg Raithel.

Raithel is co-author of a research paper on the topic published online May 31 in the journal Physical Review E. The other author is U-M research fellow Betty Slama-Eliau.

The standard method used to characterize biological molecules like proteins involves crystallizing them, then analyzing their structure by bombarding the crystals with X-rays, a technique called X-ray crystallography. But the method cannot be used on many of the proteins of highest interest -- such as cell-membrane proteins -- because there's no way to crystallize those molecules.

"So we came up with this idea that one could use, instead of a conventional crystal, an optically induced crystal in order to get the crystallization of a sample that could be suitable for structural analysis," said Raithel, professor of physics and associate chair of the department.

To move toward that goal, Raithel and his colleagues are developing the laser technique using microscopically small plastic spheres instead of the molecules. Other researchers have created 3-D optically induced crystals, but Raithel said the crystals his team created are denser than those previously achieved.

The process involves shining laser beams through two opposed microscope lenses, one directly beneath the other. Two infrared laser beams are directed through each lens, and they meet at a common focal point on a microscope slide that holds thousands of plastic nanoparticles suspended in a drop of water.

The intersecting laser beams create electric fields that vary in strength in a regular pattern that forms a 3-D grid called an optical lattice. The nanoparticles get sucked into regions of high electric-field strength, and thousands of them align to form optically induced crystals. The crystals are spherical in shape and about 5 microns in diameter. A micron is one millionth of a meter.

Imagine an egg crate containing hundreds of eggs. The cardboard structure of the crate is the optical lattice, and each of the eggs represents one of the nanoparticles. Stack several crates on top of each other and you get a 3-D crystal structure.

"The crate is the equivalent of the optical lattice that the laser beams make," Raithel said. "The structure of the crystal is determined by the egg carton, not by the eggs."

The optical crystals dissipate as soon as the laser is switched off.

The research was funded by the National Science Foundation.


Story Source:

The above story is based on materials provided by University of Michigan. Note: Materials may be edited for content and length.


Journal Reference:

  1. B. Slama-Eliau, G. Raithel. Three-dimensional arrays of submicron particles generated by a four-beam optical lattice. Physical Review E, 2011; 83 (5) DOI: 10.1103/PhysRevE.83.051406

Cite This Page:

University of Michigan. "Lasers used to form 3-D crystals made of nanoparticles." ScienceDaily. ScienceDaily, 3 June 2011. <www.sciencedaily.com/releases/2011/06/110601091441.htm>.
University of Michigan. (2011, June 3). Lasers used to form 3-D crystals made of nanoparticles. ScienceDaily. Retrieved September 30, 2014 from www.sciencedaily.com/releases/2011/06/110601091441.htm
University of Michigan. "Lasers used to form 3-D crystals made of nanoparticles." ScienceDaily. www.sciencedaily.com/releases/2011/06/110601091441.htm (accessed September 30, 2014).

Share This



More Matter & Energy News

Tuesday, September 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Do Video Games Trump Brain Training For Cognitive Boosts?

Do Video Games Trump Brain Training For Cognitive Boosts?

Newsy (Sep. 29, 2014) More and more studies are showing positive benefits to playing video games, but the jury is still out on brain training programs. Video provided by Newsy
Powered by NewsLook.com
CERN Celebrates 60 Years of Science

CERN Celebrates 60 Years of Science

Reuters - Business Video Online (Sep. 29, 2014) CERN, the European Organisation for Nuclear Research, celebrates 60 years of bringing nations together through science. As Joanna Partridge reports from inside the famous science centre it's also planning to turn the Large Hadron Collider particle accelerator back on after an upgrade. Video provided by Reuters
Powered by NewsLook.com
This 'Invisibility Cloak' Is Simpler Than Most

This 'Invisibility Cloak' Is Simpler Than Most

Newsy (Sep. 28, 2014) Researchers from the University of Rochester have created a type of invisibility cloak with simple focal lenses. Video provided by Newsy
Powered by NewsLook.com
New Corvette Can Secretly Record Convos And Get You Arrested

New Corvette Can Secretly Record Convos And Get You Arrested

Newsy (Sep. 28, 2014) The 2015 Corvette features valet mode – which allows the owner to secretly record audio and video – but in many states that practice is illegal. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins