Synopsis: Can Spasers go Electric?

Calculations suggest that there are ways to drive spasers—the nanoplasmonic counterparts of lasers—by standard electrical currents.
Synopsis figure
M. Stockman/Georgia State University

Spasers (short for surface plasmon amplification by stimulated emission of radiation) are the nanoplasmonic analogs of lasers: instead of photons, spasers generate coherent surface plasmons (collective electron oscillations at the surface of a metal) in a resonant nanoparticle. Heralded as ideal sources of coherent optical fields at the nanoscale, spasers could be combined with electronics on a chip and, as argued by some, might even replace conventional transistors, being just as small but 1000 times faster.

To allow integration with electronics, a crucial development would be the realization of a spaser pumped by electrical currents, rather than by the bulkier lasers used thus far. But recent theoretical papers have argued that electrically driven nanospasers would require unrealistically high currents. Now, writing in Physical Review Letters, Dabing Li at the Changchun Institute of Optics, Fine Mechanics and Physics of the Chinese Academy of Sciences, and Mark Stockman at Georgia State University in Atlanta present a theoretical proposal for a nanospaser device that is pumped electrically via a nanowire.

The authors study a scheme in which the spaser core is a nanoparticle made of gold, silver, or aluminum. They analyze the spaser behavior, calculating the threshold for “spasing” (in analogy with lasing, spasing occurs when gain is sufficient to overcome the losses), the currents required for reaching this threshold, and the number of quanta generated above the threshold. The results suggest that, with proper materials choice, electrical pumping would be feasible.

Compared with previous work, the key novelty of the authors’ approach is that electron transport occurs in a fully quantum, rather than classical, regime. The ball falls now in the court of experimentalists to prove whether quantum effects hold the key to this promising technology. – Matteo Rini


Features

More Features »

Announcements

More Announcements »

Subject Areas

NanophysicsOptoelectronics

Previous Synopsis

Next Synopsis

Related Articles

Viewpoint: Reservoir Computing Speeds Up
Nonlinear Dynamics

Viewpoint: Reservoir Computing Speeds Up

A brain-inspired computer made with optoelectronic parts runs faster thanks to a hardware redesign, recognizing simple speech at the rate of 1 million words per second. Read More »

Focus: Nanochannel Could Separate Mixed Fluids
Fluid Dynamics

Focus: Nanochannel Could Separate Mixed Fluids

Calculations show that capillary forces affecting a fluid mixture flowing through a nanochannel could be used to separate the mixture. Read More »

Focus: Negative Resistance with a Single Atom
Nanophysics

Focus: Negative Resistance with a Single Atom

Current flowing through a single silicon atom can be made to decrease with increasing voltage, potentially allowing the integration of a new type of component into microelectronic circuits. Read More »

More Articles