INTRODUCTION TO LASERS
TECHNOLOGY EDUCATION
SCARSDALE MIDDLE SCHOOL
LASER PRESENTATION 2
Many of the pictures for this “LASER” presentation camefrom www.howstuffworks.com.
LASER PRESENTATION 3
LASER
• Originally LASER was an acronym for Light Amplification by the Stimulated Emission of Radiation.
• Now laser is a word used to identify this type of equipment or the light it produces.
LASER PRESENTATION 4
The Atom
Different electron orbits represent different energy levels.
LASER PRESENTATION 5
The Electron
Applying energy to an electron causes it to jumpto a higher orbit.
LASER PRESENTATION 6
The Photon
When the electron drops back to its original orbit itreleases a particle called a photon. Light is made up of photons.
LASER PRESENTATION 7
Wavelength of Light
Light moves in waves that are similarto ripples in water.
Light is an example of electromagnetic radiation: It doesn’trequire a medium to pass through
LASER PRESENTATION 8
Wavelength of Light1 CYCLE
Wavelength (): The distance the wave travels in one cycle.
Frequency (f): The number of times a cyclerepeats in one second (Hertz,formerley cycles/second).
= c f
LASER PRESENTATION 9
Wavelength of Light HERTZ ENERGY
~ 400 nanometers
~ 700 nanometers
HIGHER
FREQUENCY
LESS
ENERGY
LASER PRESENTATION 10
1 NANOMETER IS ONE BILLIONTH OF A METER
A human hair is about 80,000nanometers in diameter.
That’s about 115 times the wavelength () of red light.
LASER PRESENTATION 11
Light BulbLight is not focused
Light is made up of many colors (wavelengths)
Light is not coherent
LASER PRESENTATION 12
White LightLight From A Light Bulb
•All colors (wavelengths).
•More longer wavelengths.
•Light is notcoherent.
•Light is notfocused.
LASER PRESENTATION 13
Laser Light Light is very focused
Light is made up of one color (wavelength)
Light is coherent
LASER PRESENTATION 14
Laser LightLight From A Laser
•One color (wavelength).
•Light is coherent.
•Light is focused.
LASER PRESENTATION 15
Theodore MaimanFirst Ruby Laser
1960
LASER PRESENTATION 16
How a Laser Works
ATOM
PHOTONS
PHOTONS FROM EXTERNALSOURCE STRIKE ATOMSIN THE ROD.
ATOMS RELEASE MORE PHOTONS(STIMULATED EMISSION OF RADIATION)WHICH STRIKE OTHER ATOMS CONTINUING THE PROCESS (AMPLIFICATION).
MANY PHOTONS ARE REFLECTEDBACK AND FORTH BY THE MIRRORSAT EACH END OF THE ROD.
COHERENT, FOCUSED PHOTONS LEAVE THE ROD THROUGH A SLIT IN THE MIRROR.
MIRROR
MIRROR
SLIT
LIGHT AMPLIFICATION BY THE STIMULATED EMISSION OF RADIATION
LASER PRESENTATION 17
Ruby Laser
LASER PRESENTATION 18
Types of LasersBased on the Material Used in the Laser
Classes of LasersBased on the Biological Damage the Laser
Can Cause
LASER PRESENTATION 19
Laser Type Wavelength (nm)
•Argon fluoride (UV) 193•Krypton fluoride (UV) 248•Nitrogen (UV) 337•Argon (blue) 488•Argon (green) 514•Helium neon (green) 543•Helium neon (red) 633•Rhodamine 6G dye (tunable) 570 - 650•Ruby (CrAlO3) (red) 694•Nd:Yag (NIR) 1064•Carbon dioxide (FIR) 10600
Typical Lasers and Their Emission Wavelengths
LASER PRESENTATION 20
Optical Damage Threshold TestNASA Research Center
The Optical Damage Threshold test station at NASA Langley Research Center has three lasers: a high-energy pulsed ND:Yag laser,a Ti:sapphire laser and an alignment HeNe laser.
LASER PRESENTATION 21
Classes of LasersBased on the Biological Damage the Laser Can
CauseClass I: Lasers that don’t produce any harmful
radiation.Class II: Lasers that are harmful if viewed for
long periods of time. (The assumption is that people wouldn’t let this happen.)
Class III: Lasers that are dangerous for short exposure. (Many laser pointers are class III lasers!)
Class IV: Lasers that can blind or burn after a very brief exposure. These can only be used under very controlled conditions.
LASER PRESENTATION 22
LASER WEAPONS“Do you expect me to talk Goldfinger?”“No Mr. Bond, I expect you to die.”
LASER PRESENTATION 23
Laser Gun Sights
LASER PRESENTATION 24
Multiple Integrated Laser Engagement SystemMILES (2000)
“Laser Tag” for Soldiers
LASER PRESENTATION 25
Laser Targeting SystemAircraft Mounted
LASER PRESENTATION 26
Laser Guided Bomb(“Smart” Bomb)
Optical sensor
Guidance system
Control surfaces
LASER PRESENTATION 27
Laser Targeting
1. Laser targetingsystem “paints”target.
2. Laser guided weapon tracks
laser spot ontarget.
LASER PRESENTATION 28
Laser Targeting SystemGround Based
LASER PRESENTATION 29
Laser Targeting CountermeasuresAN/VVR-1 Laser Warning Receiver System
System detectsthe targetinglaser.
Countermeasuresinclude smoke,brighter laserbeam, maneuvering,etc.
LASER PRESENTATION 30
Laser Guided MissileHellfire laser guided missiles mounted on a US Army Apache helicopter gunship.
Newer variation (Hellfire II) replaces laser guidancewith radar guidance to penetrate smoke and cloud cover.
LASER PRESENTATION 31
ABLAirborne LaserAntimissile Weapon
United States Air Force
LASER PRESENTATION 32
ABLNose Turret
CO2 Targeting Laser
LASERS IN MANUFACTURING
LASER PRESENTATION 34
Punch Press
Punch Press Problems•Dangerous to operate.•Required long runs to be profitable.
Typical Stamped Parts
LASER PRESENTATION 35
Laser Cutter
LASER PRESENTATION 36
Computer Controlof Laser Cutter Equipment
•No human contactwith the part during operation.
•Computer programcan be loaded quickly. Shorter runs are nowprofitable.
LASER PRESENTATION 37
Laser Welding
Welded Parts
LASER PRESENTATION 38
Laser WeldingWelded car door panel made from three types of steel.
LASER PRESENTATION 39
Laser Stereolithography(SLA)
LASER PRESENTATION 40
Part Produced by
SLA
LASER PRESENTATION 41
LASERS IN MEDICINE
LASER PRESENTATION 42
Laser Eye SurgeryLAser in SItu Keratomileusis (Lasik)
1. Tiny flap of outercornea folded back.
2. Laser removes tissuefrom remaining corneato change its shape.
3. Flap of outercornea thenreattached.
LASER PRESENTATION 43
Laser Tattoo Removal(Doesn’t always work!)
The laser beam breaks up the pigments in the tattoointo small particles. Then the body’s immune systemattacks and destroys them.
LASER PRESENTATION 44
Laser Dentistry
Laser
Water jet
•Major advantage is no “drilling sound”.•Can’t be used on existing metal fillings.
LASER PRESENTATION 45
LASER TESTING AND MEASURING
LASER PRESENTATION 46
Laser Bar Code Scanning
Universal Product Code (UPC) Label
LASER PRESENTATION 47
Barcode on a UPS Label
LASER PRESENTATION 48
Barcode Scanner
LASER PRESENTATION 49
Railroad Car SortingUsing Barcode Scanning
Labels were often too dirty for thescanners to read.
LASER PRESENTATION 50
Laser Surface Roughness Tester
LASER PRESENTATION 51
Laser Level
LASER PRESENTATION 52
Laser Speed MeasurementNew York State Police
LASER PRESENTATION 53
Telescope Calibration Lick Observatory
The adaptive optics system at the Shane 3 meter telescope utilizes a 20-watt sodium laser to put a false star in the sky. The system uses the star to compensate for atmospheric disturbances, creating sharper, clearer images of the objects observed.
LASER PRESENTATION 54
LASER COMMUNICATION
LASER PRESENTATION 55
Laser Printer
Corona Wire Discharge Lamp
LASER PRESENTATION 56
Laser DiskPit
Land
Beam reflects:logical 1.
Beam doesn’t reflect:logical 0.
LASER PRESENTATION 57
Laser Disk Drive
LASER PRESENTATION 58
MODULATIONSuperimposing a weak signal
on a strong one
MODULATOR: Combines audio signal and laser beam.
DEMODULATOR: Removes audio signal from the modulated laser beam.
MODULATED LASER BEAM: Changes in the beam representinformation in the audio signal.Audio
Laser Carrier
LASER PRESENTATION 59
FIBER OPTICSTransparent “Pipe” for Light to Travel Through
Advantages:• Very high capacity.• Can’t be tapped into.• Not affected by electromagnetic (EM) interference.• Allows light to travel around corners.
Disadvantages:• Expensive.• Can be difficult to install.
LASER PRESENTATION 60
Fiber OpticsCenter fiber optic cable has greater capacity
than any of these bundles of cable.
Top Related