How can Lasers help? Neil Broderick, Department of Physics, - - PowerPoint PPT Presentation

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How can Lasers help? Neil Broderick, Department of Physics, - - PowerPoint PPT Presentation

May 01, 2023 50 likes •686 views

How can Lasers help? Neil Broderick, Department of Physics, University of Auckland n.broderick@auckland.ac.nz Thanks to the Royal Society of New Zealand, University of Auckland, TEC and MBIE The Dodd-Walls Centre for Photonic and Quantum

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SLIDE 1

How can Lasers help?

Neil Broderick, Department of Physics, University of Auckland n.broderick@auckland.ac.nz Thanks to the Royal Society of New Zealand, University of Auckland, TEC and MBIE

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SLIDE 2

The Dodd-Walls Centre for Photonic and Quantum Technologies

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SLIDE 3

Outline

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SLIDE 4

Outline

  • What is laser light?
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SLIDE 5

Outline

  • What is laser light?
  • Communications
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SLIDE 6

Outline

  • What is laser light?
  • Communications
  • Sensors
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SLIDE 7

Outline

  • What is laser light?
  • Communications
  • Sensors
  • “blowing stuff up”
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SLIDE 8

Why Laser Light?

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SLIDE 9

Why Laser Light?

Why not a light bulb?

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SLIDE 10

Why Laser Light?

Why not a light bulb?

Lasers are a source of incredibly bright narrow frequency light!

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SLIDE 11

Laser Light

  • Laser light is single frequency ( )
  • Laser light is collimated
  • Laser light has high spatial and temporal

coherence

  • This allows you to focus a large amount of

energy into very small volumes.

Δν /ν <10−14

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SLIDE 12

Communications

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SLIDE 13

Communications

  • Every bit of information that arrives in NZ travels

along one of two optical fibres as pulses of light!

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SLIDE 14

Communications

  • Every bit of information that arrives in NZ travels

along one of two optical fibres as pulses of light!

  • Unless you are talking to some-one face to face all the

information you receive will travel as light for most of the journey.

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SLIDE 15

Communications

  • Every bit of information that arrives in NZ travels

along one of two optical fibres as pulses of light!

  • Unless you are talking to some-one face to face all the

information you receive will travel as light for most of the journey.

  • Annual global IP traffic will pass the zettabyte (1000

exabytes) threshold by the end of 2016, and will reach 2 zettabytes per year by 2019. By 2016, global IP traffic will reach 1.1 zettabytes per year, or 88.4 exabytes (nearly one billion gigabytes) per month, and by 2019, global IP traffic will reach 2.0 zettabytes per year, or 168 exabytes per month. (source cisco.com)

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SLIDE 16

Erbium doped fibre Amplifier

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SLIDE 17

Erbium doped fibre Amplifier

  • The key component enabling this is the

EDFA invented in 1987 by researchers at the University of Southampton.

  • First sub-sea all-optical fibre link using

EDFAs was installed in 1996.

  • Design life of an undersea cable and its

components is 20+ years.

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SLIDE 18

Erbium doped fibre Amplifier

  • The key component enabling this is the

EDFA invented in 1987 by researchers at the University of Southampton.

  • First sub-sea all-optical fibre link using

EDFAs was installed in 1996.

  • Design life of an undersea cable and its

components is 20+ years.

This means that optical components designed for communications wavelengths are cheap and

  • reliable. The cost can be an order of magnitude

cheaper than components designed for other wavelengths!

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SLIDE 19

Sensors

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SLIDE 20

Sensors

  • Need to decide what to measure?
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SLIDE 21

Sensors

  • Need to decide what to measure?
  • What physical quantity does that

correspond to?

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SLIDE 22

Sensors

  • Need to decide what to measure?
  • What physical quantity does that

correspond to?

  • What accuracy is needed?
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SLIDE 23

Sensors

  • Need to decide what to measure?
  • What physical quantity does that

correspond to?

  • What accuracy is needed?
  • e.g. length
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SLIDE 24

Sensors

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SLIDE 25

Sensors

Gravitational Wave detector Cost - $325 Million USD Resolution 10-18 m

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SLIDE 26

Sensors

Gravitational Wave detector Cost - $325 Million USD Resolution 10-18 m Laser Range Finder Cost - $100 NZD Resolution 1 mm

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SLIDE 27

Sensors

Gravitational Wave detector Cost - $325 Million USD Resolution 10-18 m Laser Range Finder Cost - $100 NZD Resolution 1 mm

Both devices use the same physical principals!

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SLIDE 28

Our Sensors

Canterbury Ring Lasers sensitive to rotation, can detect the rotation of the earth.

  • Fig. 2: Canterbury Ring Laser: A 6.4 m perimeter
technical , drag- tational as
  • f
pole. er
  • f
wer (SSRLs) sol- compara- prop-
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SLIDE 29

Our Sensors

Canterbury Ring Lasers sensitive to rotation, can detect the rotation of the earth.

  • Fig. 2: Canterbury Ring Laser: A 6.4 m perimeter
technical , drag- tational as
  • f
pole. er
  • f
wer (SSRLs) sol- compara- prop-

Laser Doppler Vibrometer can detect ripeness of fruit!

  • r cracks in wine bottles.
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SLIDE 30

More Sensors

Fluorescence sensing Used for real time bacteria counting Laser absorption spectroscopy

  • Can detect trace amounts of gases.
  • Works best in the mid-IR and we are

developing new lasers to access this region.

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SLIDE 31

Object detection

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SLIDE 32

Object detection

Mercedes-Benz factory

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SLIDE 33

Object detection

Mercedes-Benz factory

  • Uses structured light to

test car parts for imperfections.

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SLIDE 34

Object detection

Mercedes-Benz factory

  • Uses structured light to

test car parts for imperfections.

  • Resolution is sub mm.
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SLIDE 35

Object detection

Mercedes-Benz factory

  • Uses structured light to

test car parts for imperfections.

  • Resolution is sub mm.
  • Test is quick and simple.
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SLIDE 36

Object detection

Mercedes-Benz factory

  • Uses structured light to

test car parts for imperfections.

  • Resolution is sub mm.
  • Test is quick and simple.
  • Image analysis is

important, they test for aesthetic appeal rather than for structural quality.

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SLIDE 37

Object detection

Mercedes-Benz factory

  • Uses structured light to

test car parts for imperfections.

  • Resolution is sub mm.
  • Test is quick and simple.
  • Image analysis is

important, they test for aesthetic appeal rather than for structural quality.

  • Other robots test glue

thickness, alignment of welds etc.

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SLIDE 38

Structured Light Microscopy

Structured Light can be used for imaging with sub wavelength resolution, low

  • ptical powers and

high speeds.

https://www.hhmi.org/news/new-microscope-collects-dynamic-images-molecules-animate-life

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SLIDE 39

Structured Light Microscopy

Structured Light can be used for imaging with sub wavelength resolution, low

  • ptical powers and

high speeds.

https://www.hhmi.org/news/new-microscope-collects-dynamic-images-molecules-animate-life

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SLIDE 40

Measuring Time

Optical Clocks have unprecedented Precision! —Currently clocks are limited by the general relativity.

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SLIDE 41

Measuring Time

Optical Clocks have unprecedented Precision! —Currently clocks are limited by the general relativity.

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SLIDE 42

Blowing stuff up

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SLIDE 43

Blowing stuff up

  • National Ignition Facility
  • $7 Billion USD
  • 500 Tera Watts, few

picoseconds pulses

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SLIDE 44

Blowing stuff up

  • National Ignition Facility
  • $7 Billion USD
  • 500 Tera Watts, few

picoseconds pulses

  • Wicked Lasers
  • $200 USD
  • 2 Watts. Continuous Wave
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SLIDE 45

How to make a TW laser

  • Master Oscillator, power amplifier (MOPA).
Seed Amp Amp Amp

High-power 


  • utput with

characteristics determined 
 by seed

High control High power High gain High gain

  • The seed can be any laser you like.
  • You then keep adding amplifiers until you get

bored or run out of money.

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SLIDE 46

The Remarkable Increase in 
 CW Fibre Laser Power

Same picture of growth for all wavelengths and modes of operation

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SLIDE 47
  • A Learning loop can be used to optimize the source

properties for a given end application

  • The powers required for industrial processes are easily

achievable

  • Flexibility, rapid control, near-linearity of fiber MOPAs

greatly enhances scope for adaptive control

  • The technology is now available for this.

Pulsed
 source Amplification Amplitude & phase control

Process

  • Nonlinear wavelength conversion
  • Materials processing
  • Chemical reaction
  • Detection, imaging

Process
 monitoring Intelligence

Fibre Lasers – the ideal light source

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SLIDE 48

Pulsed Source

  • Patented femtosecond

technology developed at University of Auckland through a contract with Southern Photonics.

  • Robust, self-starting,

stable with push-button

  • peration.
  • Delivers 200fs pulses

that can be used directly

  • r as a seed.
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SLIDE 49

Intelligence

  • MBIE targeted

research grant with Finisar, Southern Photonics and the UoA (Photon Factory)

  • Uses a “wave-shaper”

to turn our femtosecond source into an arbitrary pulse shape. Can then be amplified further to the required power level.

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SLIDE 50

kW fibre lasers

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SLIDE 51

Applications

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SLIDE 52

Applications

  • Welding
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SLIDE 53

Applications

  • Welding
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SLIDE 54

Applications

  • Cutting
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SLIDE 55

Applications

  • Joining - Microstructuring of surfaces

allows better gluing of different materials.

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SLIDE 56

Applications

  • Additive Manufacturing
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SLIDE 57

Applications

  • Additive Manufacturing
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SLIDE 58

Conclusions

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SLIDE 59

Conclusions

  • Lasers allow for precise control of

parameters.

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SLIDE 60

Conclusions

  • Lasers allow for precise control of

parameters.

  • Can do manufacturing with greater efficiency,

less waste and individual customisation.

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SLIDE 61

Conclusions

  • Lasers allow for precise control of

parameters.

  • Can do manufacturing with greater efficiency,

less waste and individual customisation.

  • Laser based sensors can measure most

physical quantities - but you need to work out what to measure and how accurately to do it.

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SLIDE 62

Conclusions

  • Lasers allow for precise control of

parameters.

  • Can do manufacturing with greater efficiency,

less waste and individual customisation.

  • Laser based sensors can measure most

physical quantities - but you need to work out what to measure and how accurately to do it.

  • LED lighting is perhaps the most efficient use
  • f laser light to save money.
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SLIDE 63

The Dodd-Walls Centre for Photonic and Quantum Technologies

Kasper Van Wijk Cather Simpson John Harvey Frederique Vanholsbeeck