INTRODUCTION TO LASERS TECHNOLOGY EDUCATION SCARSDALE MIDDLE SCHOOL

INTRODUCTION TO LASERS TECHNOLOGY EDUCATION SCARSDALE MIDDLE SCHOOL

Many of the pictures for this LASER presentation came from www.howstuffworks.com. LASER PRESENTATION 2

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 3

The Atom Different electron orbits represent different energy levels. LASER PRESENTATION 4

The Electron Applying energy to an electron causes it to jump to a higher orbit. LASER PRESENTATION 5

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 6

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 7

Wavelength of Light 1 CYCLE Wavelength (λ): The distance the wave travels in one cycle. Frequency (f): The number of times a cycle repeats in one second (Hertz, formerley cycles/second). λ = c f LASER PRESENTATION 8

Wavelength of Light HERTZ λ ENERGY ~ 400 nanometers H I G H L E E R S S F R E E N Q E U R E G N Y C Y ~ 700 nanometers LASER PRESENTATION 9

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 (λ) of red light. LASER PRESENTATION 10

Light Bulb Light is not focused Light is made up of many colors (wavelengths) Light is not coherent LASER PRESENTATION 11

White Light Light From A Light Bulb All colors (wavelengths). More longer wavelengths. Light is not coherent. Light is not focused. LASER PRESENTATION 12

Laser Light Light is very focused Light is made up of one color (wavelength) Light is coherent LASER PRESENTATION 13

Laser Light Light From A Laser One color (wavelength). Light is coherent. Light is focused. LASER PRESENTATION 14

Theodore Maiman First Ruby Laser 1960 LASER PRESENTATION 15

MIRROR How a Laser Works MANY PHOTONS ARE REFLECTED BACK AND FORTH BY THE MIRRORS AT EACH END OF THE ROD. MIRROR SLIT PHOTONS FROM EXTERNAL SOURCE STRIKE ATOMS ATOMS RELEASE MORE PHOTONS IN THE ROD. (STIMULATED EMISSION OF RADIATION) WHICH STRIKE OTHER ATOMS CONTINUING PHOTONS THE PROCESS (AMPLIFICATION). ATOM COHERENT, FOCUSED PHOTONS LEAVE THE ROD THROUGH A SLIT IN THE MIRROR. LIGHT AMPLIFICATION BY THE STIMULATED EMISSION OF RADIATION LASER PRESENTATION 16

Ruby Laser LASER PRESENTATION 17

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 18

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) 543 Helium neon (red) 633 Rhodamine 6G dye (tunable) 570-650 Ruby (CrAlO3) (red) 694 Nd:Yag (NIR) 1064 Carbon dioxide (FIR) 10600 LASER PRESENTATION 19

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 20

Classes of Lasers Based on the Biological Damage the Laser Can Class I: Cause 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 21

LASER WEAPONS Do you expect me to talk Goldfinger? No Mr. Bond, I expect you to die. LASER PRESENTATION 22

Laser Gun Sights LASER PRESENTATION 23

Multiple Integrated Laser Engagement System MILES (2000) Laser Tag for Soldiers LASER PRESENTATION 24

Laser Targeting System Aircraft Mounted LASER PRESENTATION 25

Laser Guided Bomb ( Smart Bomb) Control surfaces Optical sensor Guidance system LASER PRESENTATION 26

Laser Targeting 2. Laser guided weapon tracks laser spot on target. 1. Laser targeting system paints target. LASER PRESENTATION 27

Laser Targeting System Ground Based LASER PRESENTATION 28

Laser Targeting Countermeasures AN/VVR-1 Laser Warning Receiver System System detects the targeting laser. Countermeasures include smoke, brighter laser beam, maneuvering, etc. LASER PRESENTATION 29

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 30

ABL Airborne Laser Antimissile Weapon United States Air Force LASER PRESENTATION 31

ABL Nose Turret CO 2 Targeting Laser LASER PRESENTATION 32

LASERS IN MANUFACTURING

Punch Press Typical Stamped Parts Punch Press Problems Dangerous to operate. Required long runs to be profitable. LASER PRESENTATION 34

Laser Cutter LASER PRESENTATION 35

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 36

Laser Welding Welded Parts LASER PRESENTATION 37

Laser Welding Welded car door panel made from three types of steel. LASER PRESENTATION 38

Laser Stereolithography (SLA) LASER PRESENTATION 39

Part Produced by SLA LASER PRESENTATION 40

LASERS IN MEDICINE LASER PRESENTATION 41

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 42

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 43

Laser Dentistry Laser Water jet Major advantage is no drilling sound. Can t be used on existing metal fillings. LASER PRESENTATION 44

LASER TESTING AND MEASURING LASER PRESENTATION 45

Laser Bar Code Scanning Universal Product Code (UPC) Label LASER PRESENTATION 46

Barcode on a UPS Label LASER PRESENTATION 47

Barcode Scanner LASER PRESENTATION 48

Railroad Car Sorting Using Barcode Scanning Labels were often too dirty for the scanners to read. LASER PRESENTATION 49

Laser Surface Roughness Tester LASER PRESENTATION 50

Laser Level LASER PRESENTATION 51

Laser Speed Measurement New York State Police LASER PRESENTATION 52

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 53

LASER COMMUNICATION LASER PRESENTATION 54

Laser Printer Corona Wire Discharge Lamp LASER PRESENTATION 55

Laser Disk Pit Land Beam doesn t reflect: logical 0. Beam reflects: logical 1. LASER PRESENTATION 56

Laser Disk Drive LASER PRESENTATION 57

MODULATION Superimposing a weak signal on a strong one Audio MODULATED LASER BEAM: Changes in the beam represent information in the audio signal. Laser Carrier MODULATOR: Combines audio signal and laser beam. DEMODULATOR: Removes audio signal from the modulated laser beam. LASER PRESENTATION 58

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 59

Fiber Optics Center fiber optic cable has greater capacity than any of these bundles of cable. LASER PRESENTATION 60