Featured Research

from universities, journals, and other organizations

Design Of Microlasers Could Be Improved, Based On New Theoretical Analysis

Date:
January 24, 2009
Source:
Optical Society of America
Summary:
Tiny disk-shaped lasers as small as a speck of dust could one day beam information through optical computers. Unfortunately, a perfect disk will spray light out, not as a beam, but in all directions. New theoretical results explain how adding a small notch to the disk edge provides a single outlet for laser light to stream out.

Tiny disk-shaped lasers as small as a speck of dust could one day beam information through optical computers. Unfortunately, a perfect disk will spray light out, not as a beam, but in all directions. New theoretical results explain how adding a small notch to the disk edge provides a single outlet for laser light to stream out.

Related Articles


To increase the speed of computers and telecommunication networks, researchers are looking to replace electrical currents with beams of light that would originate from small semiconductor lasers. However, shrinking lasers down to a few micrometers in size is not easy. The typical laser builds up its concentrated light beam by bouncing light rays, or modes, back and forth inside a reflective cavity. This linear design is not practical for microlasers. Instead, scientists discovered in 1992 that they could get light amplification by having rays bounce around in a circle inside a small flat disk. These light rays are called "whispering gallery modes" because they are similar to sound waves that travel across a room by skimming along a curved wall or ceiling.

The problem is that a disk is rotationally invariant, so there is no preferred direction for the amplified light to escape. Many microlaser designs end up shooting light out in multiple directions within the plane of the disk. "The experimentalists have a holy grail of unidirectional emission in microlasers," says Martina Hentschel of the Max Planck Institute for the Physics of Complex Systems.

In the past few years, some progress has been made with so-called spiral microlasers, which have a tiny notch that resembles the outer opening of a snail shell. Certain experiments have shown that light tends to propagate in a single direction from the notch. But other experiments have not been so lucky. In order to understand these contrasting results, Hentschel and her colleague Tae-Yoon Kwon have performed a systematic study of spiral microlasers using a state-of-the-art theoretical description.

Physicists typically treat the light rays trapped inside a cavity as if they were billiard balls bouncing off walls, Hentschel explains. Some light rays escape, but those rays that just barely graze the inside surface are fully reflected back into the cavity (this being the same effect that channels light beams along optical fibers). Unfortunately, this simple "billiard" model is not sufficient for explaining spiral microlasers, Hentschel says.

Hentschel and Kwon therefore chose a more sophisticated model based on the electromagnetic wave and laser equations. This framework allowed the researchers to control what part of the semiconductor material would be excited, or "pumped," to a light-emitting state. Numerical calculations showed that the two whispering gallery modes inside a spiral cavity—one traveling clockwise, the other counterclockwise—are coupled together, but only one of these modes is able to escape out through the spiral's notch.

To maximize this unidirectional emission, the researchers found that the notch size should be roughly twice the wavelength of the light. Moreover, the pumping needs to be confined to the rim of the spiral, specifically the outer 10 percent. These parameters could aid in the design of better-collimated microlasers. "The optimal geometry and boundary pumping is very useful to know for an experimentalist," Hentschel says.


Story Source:

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


Journal Reference:

  1. Spiral Microlasers. Optics Letters, Vol. 34 No. 2, January 15, 2009

Cite This Page:

Optical Society of America. "Design Of Microlasers Could Be Improved, Based On New Theoretical Analysis." ScienceDaily. ScienceDaily, 24 January 2009. <www.sciencedaily.com/releases/2009/01/090122152715.htm>.
Optical Society of America. (2009, January 24). Design Of Microlasers Could Be Improved, Based On New Theoretical Analysis. ScienceDaily. Retrieved March 4, 2015 from www.sciencedaily.com/releases/2009/01/090122152715.htm
Optical Society of America. "Design Of Microlasers Could Be Improved, Based On New Theoretical Analysis." ScienceDaily. www.sciencedaily.com/releases/2009/01/090122152715.htm (accessed March 4, 2015).

Share This


More From ScienceDaily



More Matter & Energy News

Wednesday, March 4, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Forensic Holodeck Creates 3D Crime Scenes

Forensic Holodeck Creates 3D Crime Scenes

Reuters - Innovations Video Online (Mar. 3, 2015) A holodeck is no longer the preserve of TV sci-fi classic Star Trek, thanks to researchers from the Institute of Forensic Medicine Zurich, who have created what they say is the first system in the world to visualise the 3D data of forensic scans. Jim Drury saw it in operation. Video provided by Reuters
Powered by NewsLook.com
Solar Plane Passes New Test Ahead of World Tour

Solar Plane Passes New Test Ahead of World Tour

AFP (Mar. 2, 2015) A solar-powered plane made a third successful test flight in the United Arab Emirates on Monday ahead of a planned round-the-world tour to promote alternative energy. Duration: 01:05 Video provided by AFP
Powered by NewsLook.com
Electric Hydrofoiling Watercraft Delivers Eco-Friendly Thrills

Electric Hydrofoiling Watercraft Delivers Eco-Friendly Thrills

Reuters - Innovations Video Online (Mar. 2, 2015) The Quadrofoil is a high-tech electric personal watercraft that its makers call a &apos;sports car for the water&apos;. When it hits 10 km/h, the Slovenian-engineered Quadrofoil is lifted above the water onto four wing-like hydrofoils where it &apos;flies&apos; above the surface with minimal water resistance. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Everything You Need To Know About Mobile Payments In 2015

Everything You Need To Know About Mobile Payments In 2015

Newsy (Mar. 2, 2015) This year, mobile payments might finally catch on. Here are the things you need to know to stay on top of the latest developments. 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