NANOLASERS
When
lasers start getting down to the nanoscale, they run up against the diffraction
limit where the size of the laser cannot be smaller than the wavelength of
light it emits. But researchers have shown that nanoscale plasmonic lasers can
reach an optical mode well below this limit by confining light of very short
wavelengths through the use of surface plasmons oscillations of electrons that
occur at the junction of a metal and an insulator. This has revitalized the
hope that chips populated with these plasmonic nanolasers could make possible computer processors run by
light rather than electrons.
Now
researchers at Northwestern University have developed a
new design for plasmonic nanolasers that are the size of a virus particle and
capable of operating at room temperature.
"The reason can fabricate nanolasers with sizes
smaller than that allowed by diffraction is because to made the lasing cavity
out of metal nanoparticle dimers -- structures with a 3-D bowtie' shape"
The bowtie geometry allowed the nanoparticles to achieve an
antenna effect and suffer only minimal metal “losses”. Typically, plasmon
nanolaser cavities have suffered from both metal and radiation losses that
required them to be operated at cryogenic temperatures. The antenna effect
allows for lasing to occur from an "electromagnetic hot spot" found that when arranged in an array, the 3-D
bowtie resonators could emit light at specific angles according to the lattice
parameters,"
Dinesh S
Dept. of Information
Science & Engineering
Brindavan College of
Engineering, Bangalore
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