Featured Research

from universities, journals, and other organizations

Nano-optics: Getting the most out of tiny lasers

Date:
July 8, 2014
Source:
The Agency for Science, Technology and Research (A*STAR)
Summary:
Semiconductor optical devices are becoming increasingly commonplace. For example, light-emitting diodes, as they become more power efficient, are rapidly replacing conventional light bulbs. Lasers too are now found in every barcode scanner and compact-disc reader. An off-center waveguide enables light to be efficiently extracted from nanoscale lasers.

Computer simulations show that efficient light extraction from a nanoring plasmonic laser can occur when a waveguide is connected flush with one edge of the device.
Credit: Copyright 2014 C. Lee et al. Modified from Ref. 1 and licensed under CC BY-NC 3.0

An off-center waveguide enables light to be efficiently extracted from nanoscale lasers.

Related Articles


Semiconductor optical devices are becoming increasingly commonplace. For example, light-emitting diodes, as they become more power efficient, are rapidly replacing conventional light bulbs. Lasers too are now found in every barcode scanner and compact-disc reader.

When designing these devices, a crucial consideration is how best to get the light generated within the solid material out into the real world. Chee-Wei Lee at the A*STAR Data Storage Institute, Singapore, and international colleagues have now proposed a light-extraction scheme that is capable of transferring over half the light created by a submicrometer-scale laser into a waveguide.

Plasmonic lasers are the smallest lasers created to date -- they can even be smaller than the wavelength of the light they emit. This counterintuitive property results from plasmons, which are hybrid electron-light particles created by coupling light with electrons in a metal.

Lee and his team considered the simplest plasmonic laser: a ring of a light-emitting semiconductor coated with a thin silver layer. Light can travel round and round inside the ring, which provides the optical cavity required in most laser devices. What is more, this tiny laser can be bonded onto a silicon substrate to make it compatible with compact photonics-on-a-chip technology. Lee and his team used computer simulations to demonstrate that high extraction efficiency is obtained when a waveguide (a light-carrying submicrometer-wide semiconductor strip) is directly connected to the side of the laser.

The team used a numerical simulation technique called finite-difference time-domain to study the performance of waveguides of different widths connected at different points on the laser. Their models revealed that the optimal structure is an asymmetric one. When the extraction waveguide is displaced from the center of the ring -- so that the waveguide is flush with the edge of the cavity -- it produces a peak out-coupling efficiency of 56 per cent (see image). "Our scheme, based on directly joining a waveguide, enhances light extraction by splitting the plasmon mode," explains Lee.

Scientists have previously extracted light from plasmonic lasers by running a waveguide extremely close to, but not touching, the cavity ring. Light can leak across the gap between the laser and the waveguide through an effect called evanescent coupling. But this approach requires precise control over the gap size and the optical properties of the material in the gap. The method developed by the team, however, can be implemented using much simpler device fabrication. "We are now in the process of actually realizing such a device," says Lee.


Story Source:

The above story is based on materials provided by The Agency for Science, Technology and Research (A*STAR). Note: Materials may be edited for content and length.


Journal Reference:

  1. Chee-Wei Lee, Gurpreet Singh, Qian Wang. Light extraction – a practical consideration for a plasmonic nano-ring laser. Nanoscale, 2013; 5 (22): 10835 DOI: 10.1039/C3NR04327D

Cite This Page:

The Agency for Science, Technology and Research (A*STAR). "Nano-optics: Getting the most out of tiny lasers." ScienceDaily. ScienceDaily, 8 July 2014. <www.sciencedaily.com/releases/2014/07/140708111015.htm>.
The Agency for Science, Technology and Research (A*STAR). (2014, July 8). Nano-optics: Getting the most out of tiny lasers. ScienceDaily. Retrieved November 21, 2014 from www.sciencedaily.com/releases/2014/07/140708111015.htm
The Agency for Science, Technology and Research (A*STAR). "Nano-optics: Getting the most out of tiny lasers." ScienceDaily. www.sciencedaily.com/releases/2014/07/140708111015.htm (accessed November 21, 2014).

Share This


More From ScienceDaily



More Matter & Energy News

Friday, November 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Toyota's Hydrogen Fuel-Cell Green Car Soon Available in the US

Toyota's Hydrogen Fuel-Cell Green Car Soon Available in the US

AFP (Nov. 21, 2014) Toyota presented its hydrogen fuel-cell compact car called "Mirai" to US consumers at the Los Angeles auto show. The car should go on sale in 2015 for around $60.000. It combines stored hydrogen with oxygen to generate its own power. Duration: 01:18 Video provided by AFP
Powered by NewsLook.com
Google Announces Improvements To Balloon-Borne Wi-Fi Project

Google Announces Improvements To Balloon-Borne Wi-Fi Project

Newsy (Nov. 21, 2014) In a blog post, Google said its balloons have traveled 3 million kilometers since the start of Project Loon. Video provided by Newsy
Powered by NewsLook.com
NSA Director: China Can Damage US Power Grid

NSA Director: China Can Damage US Power Grid

AP (Nov. 20, 2014) China and "one or two" other countries are capable of mounting cyberattacks that would shut down the electric grid and other critical systems in parts of the United States, according to Adm. Michael Rogers, director of the National Security Agency and hea Video provided by AP
Powered by NewsLook.com
Latest Minivan Crash Tests Aren't Pretty

Latest Minivan Crash Tests Aren't Pretty

Newsy (Nov. 20, 2014) Five minivans were put to the test in head-on crash simulations by the Insurance Institute for Highway Safety. 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