News Article

Scientists Take Step Towards Practical Metamaterial Light Emitters

Hyperbolic metamaterial structure can both enhance and capture quantum dot light emissions

A team from City College, City University of New York (CUNY), Purdue University and the University of Alberta has demonstrated how to both enhance light emission and capture light from metamaterials embedded with light emitting quantum dots. The breakthrough, they believe, could lead to a range of applications including ultrafast LEDs, nanoscale lasers and efficient single photon sources.

In the demonstration, the team, led by physicist Vinod Menon, used what are known as hyperbolic metamaterials to enhance the light emission properties of the quantum dots, which are used for local excitation of high-k modes. 

Metamaterials are artificial materials created with subwavelength repeating structures that can control and process electromagnetic radiation in unusual ways. Hyperbolic metamaterials are a type of metamaterial designed to display indefinite dispersion. Their properties include enhancement of spontaneous emission, as well as superlensing effects.

While enhancement in light emission from such systems has been shown by different groups, including Menon's, in the past, they were not useful in a practical way since light did not come out easily from them. The present work takes the first step towards developing practical light emitters based on metamaterials.

The active hyperbolic metamaterial structure consisted of seven alternating layers of Al2O3 at 20nm thickness, silver at 12nm, with 1.2nm germanium inbetween. A spin-coated active layer of quantum dots was embedded in the middle of the fifth Al2O3 layer. The team engineered an efficient light extraction scheme using a high-index-contrast bullseye grating, which was deposited on top.

"We've shown both an increase in light emission and were able to extract light." added Professor Menon, whose team included City College PhD students Tal Galfsky and H.N.S. Krishnamoothy

"˜Active hyperbolic metamaterials: enhanced spontaneous emission and light extraction' by Galfsky et al, appears in Optica, Vol. 2, Issue 1, pp. 62-65 (2015)

AngelTech Live III: Join us on 12 April 2021!

AngelTech Live III will be broadcast on 12 April 2021, 10am BST, rebroadcast on 14 April (10am CTT) and 16 April (10am PST) and will feature online versions of the market-leading physical events: CS International and PIC International PLUS a brand new Silicon Semiconductor International Track!

Thanks to the great diversity of the semiconductor industry, we are always chasing new markets and developing a range of exciting technologies.

2021 is no different. Over the last few months interest in deep-UV LEDs has rocketed, due to its capability to disinfect and sanitise areas and combat Covid-19. We shall consider a roadmap for this device, along with technologies for boosting its output.

We shall also look at microLEDs, a display with many wonderful attributes, identifying processes for handling the mass transfer of tiny emitters that hold the key to commercialisation of this technology.

We shall also discuss electrification of transportation, underpinned by wide bandgap power electronics and supported by blue lasers that are ideal for processing copper.

Additional areas we will cover include the development of GaN ICs, to improve the reach of power electronics; the great strides that have been made with gallium oxide; and a look at new materials, such as cubic GaN and AlScN.

Having attracted 1500 delegates over the last 2 online summits, the 3rd event promises to be even bigger and better – with 3 interactive sessions over 1 day and will once again prove to be a key event across the semiconductor and photonic integrated circuits calendar.

So make sure you sign up today and discover the latest cutting edge developments across the compound semiconductor and integrated photonics value chain.



Search the news archive

To close this popup you can press escape or click the close icon.
Register - Step 1

You may choose to subscribe to the Compound Semiconductor Magazine, the Compound Semiconductor Newsletter, or both. You may also request additional information if required, before submitting your application.

Please subscribe me to:


You chose the industry type of "Other"

Please enter the industry that you work in:
Please enter the industry that you work in:
Live Event