# INTRODUCTION TO LASERS

## Presentation on theme: "INTRODUCTION TO LASERS"— Presentation transcript:

INTRODUCTION TO LASERS
TECHNOLOGY EDUCATION SCARSDALE MIDDLE SCHOOL

Many of the pictures for this “LASER” presentation came
from LASER PRESENTATION

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

The Atom Different electron orbits represent different energy levels.
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The Electron Applying energy to an electron causes it to jump
to a higher orbit. LASER PRESENTATION

The Photon When the electron drops back to its original orbit it
releases a particle called a photon. Light is made up of photons. LASER PRESENTATION

Wavelength of Light Light moves in waves that are similar
to ripples in water. Light is an example of electromagnetic radiation: It doesn’t require a medium to pass through LASER PRESENTATION

Wavelength of Light c f Wavelength (): The distance the wave travels
1 CYCLE Wavelength (): The distance the wave travels in one cycle. Frequency (f): The number of times a cycle repeats in one second (Hertz, formerley cycles/second).  = c f LASER PRESENTATION

Wavelength of Light ~ 700 nanometers HERTZ  ENERGY ~ 400 nanometers
HIGHER FREQUENCY LESS ENERGY LASER PRESENTATION

1 NANOMETER IS ONE BILLIONTH OF A METER
A human hair is about 80,000 nanometers in diameter.  That’s about 115 times the wavelength () of red light. LASER PRESENTATION

Light Bulb Light is not focused Light is made up of many colors (wavelengths) Light is not coherent
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White Light Light From A Light Bulb All colors (wavelengths).
More longer wavelengths. Light is not coherent. focused. LASER PRESENTATION

Laser Light Light is very focused Light is made up of one color (wavelength) Light is coherent
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Laser Light Light From A Laser One color (wavelength).
Light is coherent. Light is focused. LASER PRESENTATION

Theodore Maiman First Ruby Laser 1960
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How a Laser Works LASER PRESENTATION

Ruby Laser LASER PRESENTATION

Types of Lasers Based on the Material Used in the Laser
Classes of Lasers Based on the Biological Damage the Laser Can Cause LASER PRESENTATION

Typical Lasers and Their Emission Wavelengths
Laser Type Wavelength (nm) Argon fluoride (UV) 193 Krypton fluoride (UV) 248 Nitrogen (UV) 337 Argon (blue) 488 Argon (green) 514 Helium neon (green) Helium neon (red) 633 Rhodamine 6G dye (tunable) Ruby (CrAlO3) (red) 694 Nd:Yag (NIR) Carbon dioxide (FIR) LASER PRESENTATION

Optical Damage Threshold Test NASA 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

Classes of Lasers Based on the Biological Damage the Laser Can Cause
Class 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

LASER WEAPONS “Do you expect me to talk Goldfinger?”
“No Mr. Bond, I expect you to die.” LASER PRESENTATION

Laser Gun Sights LASER PRESENTATION

 Multiple Integrated Laser Engagement System MILES (2000) “Laser Tag” for Soldiers
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Laser Targeting System Aircraft Mounted
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Laser Guided Bomb (“Smart” Bomb)
Control surfaces Guidance system Optical sensor LASER PRESENTATION

Laser Targeting 2. Laser guided weapon tracks laser spot on target.
system “paints” target. LASER PRESENTATION

Laser Targeting System Ground Based
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Laser Targeting Countermeasures AN/VVR-1 Laser Warning Receiver System
detects the targeting laser. Countermeasures include smoke, brighter laser beam, maneuvering, etc. LASER PRESENTATION

Laser Guided Missile Hellfire laser guided missiles mounted on a
US Army Apache helicopter gunship. Newer variation (Hellfire II) replaces laser guidance with radar guidance to penetrate smoke and cloud cover. LASER PRESENTATION

ABL Airborne Laser Antimissile Weapon United States Air Force
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ABL Nose Turret CO2 Targeting Laser LASER PRESENTATION

LASERS IN MANUFACTURING

Punch Press Typical Stamped Parts Punch Press Problems
Dangerous to operate. Required long runs to be profitable. LASER PRESENTATION

Laser Cutter LASER PRESENTATION

Computer Control of Laser Cutter Equipment
No human contact with the part during operation. Computer program can be loaded quickly. Shorter runs are now profitable. LASER PRESENTATION

Laser Welding Welded Parts LASER PRESENTATION

Laser Welding Welded car door panel made from three types of steel.
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Laser Stereolithography (SLA)
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Part Produced by SLA LASER PRESENTATION

LASERS IN MEDICINE LASER PRESENTATION

Laser Eye Surgery LAser in SItu Keratomileusis (Lasik)
2. Laser removes tissue from remaining cornea to change its shape. 1. Tiny flap of outer cornea folded back. 3. Flap of outer cornea then reattached. LASER PRESENTATION

Laser Tattoo Removal (Doesn’t always work!)
The laser beam breaks up the pigments in the tattoo into small particles. Then the body’s immune system attacks and destroys them. LASER PRESENTATION

Laser Dentistry Major advantage is no “drilling sound”.
Water jet Laser Major advantage is no “drilling sound”. Can’t be used on existing metal fillings. LASER PRESENTATION

LASER TESTING AND MEASURING
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Laser Bar Code Scanning
Universal Product Code (UPC) Label LASER PRESENTATION

Barcode on a UPS Label LASER PRESENTATION

Barcode Scanner LASER PRESENTATION

Railroad Car Sorting Using Barcode Scanning
Labels were often too dirty for the scanners to read. LASER PRESENTATION

Laser Surface Roughness Tester
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Laser Level LASER PRESENTATION

Laser Speed Measurement New York State Police
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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

LASER COMMUNICATION LASER PRESENTATION

Laser Printer Corona Wire Discharge Lamp LASER PRESENTATION

Laser Disk Land Pit Beam reflects: Beam doesn’t reflect: logical 1.
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Laser Disk Drive LASER PRESENTATION

MODULATION Superimposing a weak signal on a strong one
MODULATED LASER BEAM: Changes in the beam represent information in the audio signal. Audio Laser Carrier DEMODULATOR: Removes audio signal from the modulated laser beam. MODULATOR: Combines audio signal and laser beam. LASER PRESENTATION

FIBER OPTICS Transparent “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

Fiber Optics Center fiber optic cable has greater capacity than any of these bundles of cable.
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