Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Nano-optics: Getting the most out of tiny lasers

07.07.2014

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

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.


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. Modified from Ref. 1 and licensed under CC BY-NC 3.0

Copyright : 2014 C. Lee et al.

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(1).

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.

Reference

1. Lee, C.-W., Singh, G. & Wang, Q. Light extraction — a practical consideration for a plasmonic nano-ring laser. Nanoscale 5, 10835–10838 (2013). 

Associated links

Lee Swee Heng | Research SEA News
Further information:
http://www.researchsea.com

More articles from Process Engineering:

nachricht Dresdner scientists print tomorrow’s world
08.02.2017 | Fraunhofer-Institut für Werkstoff- und Strahltechnik IWS

nachricht New technology for mass-production of complex molded composite components
23.01.2017 | Evonik Industries AG

All articles from Process Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

NASA's fermi finds possible dark matter ties in andromeda galaxy

22.02.2017 | Physics and Astronomy

Wintering ducks connect isolated wetlands by dispersing plant seeds

22.02.2017 | Life Sciences

Impacts of mass coral die-off on Indian Ocean reefs revealed

21.02.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>