IEEE Spectrum May, 2010 - 36

even though they aren't focused by the eye.
actually die of. Let's call it heatstroke.
Therefore, if you can observe safety
We've shot high-speed video of
precautions-particularly wearing goggles
mosquitoes being zapped with 50 to 100 mJ
at all times if there's a chance of a stray
of light and found that although they keep
beam-the best option may be a visible or
flapping their wings, they lose attitude
near-infrared diode laser, or perhaps an older
control and fall out of the sky. Boost the
flashlamp-pumped laser. (SSY-1 flashlampenergy further and wings burn through
pumped neodymium-doped yttrium aluminum
or fall off, bodies emit puffs of steam, legs
garnet lasers, which can put out about one
and antennae char, and so forth. Yes, it is a
mosquito-lethal pulse a second, are often
waste of laser energy, but revenge is sweet.
available on eBay for around $100.) Of
For a backyard system, the safest route
course,making your guests wear FDA-approved
would be to insist on "eye-safe" lasers,
goggles may put a crimp in your barbecue,
which emit wavelengths that the eye will
but so would a cloud of thirsty mosquitoes.
not focus onto the retina. Alas, there are
We've found it helpful, as we assemble
few inexpensive high-power lasers at eyeand align all the components, to combine a
safe wavelengths, other than carbon dioxide
visible guide beam with the main laser beam,
lasers, whose wavelengths are so long
a color-selective beam splitter, or a filter. This
(10.6 micrometers) that they require very large
makes it much easier to see where the laser
optics to focus over any distance. We have
will go. If your system has lenses downstream
used an eye-safe near-infrared fiber laser
of the galvo, though, you will have a more
operating at 1570 nm to kill mosquitoes, but
complicated job aligning everything,
even with diligent bargain hunting at surplus
of different wavelengths
stores, you're unlikely to find a comparable
IEEE Spectrum web iconsbecause
master sheet beams
1/27/10
will be steered and focused differently.
laser for less than several thousand dollars.
Before pressing the big red button, make
Ultraviolet lasers (shorter than 400 nm)
sure your safety systems are working. Doubleare safe for the eyes, and pulsed UV light
check that the kill laser won't fire if there's
seems to be quite good for killing bugs, but
anything bigger than a mosquito in the way.
they are also expensive. In addition, shorter UV
cover the optical path with an interlock to
wavelengths, particularly 266 nm (sometimes
keep unauthorized folks away from beam
used for laser machining), can cause severe
paths (and high voltage, if any) inside.
photochemical damage, including cataracts,

All ready? Then turn everything on
and wait for your first invader to breach
the photonic plane. Track! ID! Aim! Fire!

inTelleCTual VenTures developed
the photonic fence to help in an epic
struggle against malaria and other
vicious insect-borne diseases. But
this technology could prove valuable
in other roles as well, such as
protecting crops from airborne pests
or simply tallying insect populations
rather than reducing them.
We don't really expect many Spectrum
readers will build a photonic fence for
their backyards-although given the
number of people whose first reaction to
the concept is "How soon can I get one?"
we wouldn't be shocked to hear that
some of you do. Our compliments: You
will be helping to make the world a better
place. Or at least a less itchy one.
❏
For an expanded
version of this article, including a video
of the laser in action and sidebars on ﬁghting
mosquito-borne diseases and killing bloodsucking female mosquitoes while sparing
harmless males, see http://spectrum.ieee.
TO PROBE FURTHER

org/backyard-star-wars.

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53
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Table of Contents for the Digital Edition of IEEE Spectrum May, 2010
