Lasers and some of their uses

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Lasers and (some) of their uses

• A snap-shot of lasers, large and small, and their
  applications in manufacturing, medicine, fusion
  and nano-scale engineering.

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A word from our sponsor
1917 a paper on the quantum theory of radiation.
Stimulated emission
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Lasers can be dangerous!
Whats wrong with this picture?
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Very dangerous!
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But dont believe all you read
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James Bond my (and his) first encounter with
lasers, 1964
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The very small diode laser sources

• DVD laser sources are 10mW
• IR, visible and blue now available
• Lasers can be grouped in bars, stacks or stacks
  of stacks
• 4000W c.w. now available!

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Small-scale single emitters
Same size as an old transistor can
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Diode lasers inside details

• many applications need lasers to be

• cheap

• small

• robust

• high power devices may have many elements

• 30 groups of 10 stripes

• may then be stacked in 2D

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Diode laser bars tiny!
The eye of a needle!
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Diode bars many emitters in a lineMax. cw
output power 40 - 120W
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Diode stacks Max. c.w. output power 40 - 120W
N
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High power laser diode arrays
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From small to very large. Lasers for fusion
pulsed laser output

• Glass lasers (they use doped glass as the laser
  medium) can be HUGE and occupy buildings larger
  than the school of Physics.

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Laser fusion principles inertial confinement

• compression of D-T filled glass pellet, to reach

• 100,000,000 K

• 10,000 g.cm-3

• for a picosecond

• D T fuse to form He, releasing excess energy

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Engineering is large-scale and costly
A man
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And you need a clean environment
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Large slabs of glass for amplifiers (lasers
without the end mirrors..)
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Laser glass being manufactured
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And also large mirrors to steer the light.
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Large crystals for frequency conversion infrared
to green light
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And some more, but grown much faster
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And a large laser fusion target chamber
Lawrence Livermore labs, USA
a man!
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And a bigger one again..
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Lawrence Livermore labs, California. Site of NIF
(national ignition facility)
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High power c.w. lasers.

• The ORC also makes continuous (c.w.) operation
  lasers, using doped optical fibers as the lasing
  medium.
• High power diode lasers are pump sources for
  these fiber lasers

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Lasers are dangerous (again!)
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Ultra-high powers from fibres

• Wavelength 1.1 mm

Telecom boom bust
x 1.7/year
Long-term trend 2.2 dB/year
x 1.7/year
6.6 dB/year x 10 increase in 1.5 years!
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High power fiber lasersThe laser output can cut
through2 thick sheet steel
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Fancy fiber designs can also be used.
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Laser machining
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Robotic laser welding using fiber lasers
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Lasers in medicine.

• Precise cutting, drilling, machining
• of you!
• Machining of eyes
• Tattoo removal
• Laser dentistry
• ..and more

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Cornea machining vision correction
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Tattoos expensive to have, more expensive to
have removed by laser.
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Laser dentistry goodbye to the drill
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Laser cosmetic surgery fiction
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Laser cosmetic surgery reality
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Laser direct write, and laser machining

• Focus light into photo-curable resin
• Curing only happens at the high intensity focal
  region
• Scan a pattern
• Lower the platform in the liquid resin
• Re-scan another layer

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Microstructures
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Microstructures
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Nanobull!
2 microns
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Venus de milo x 3

• Venus de milo x 3 on a human hair.

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Nano-spiders Made by light
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Other applications

• Microscopy, metrology, spectroscopy, surveying,
  range-finding, criminology, holography,
  projections, displays, TV, bar-coding,
  telecommunications, health-monitoring, remote
  sensing, thermal imaging, laser-sculpting,
  rapid-prototyping, sensing, gas-detection, laser
  scalpels.you name it!