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  1. 1. WHAT IS A LASER?A Laser is a device that produces a narrow beam of coherentlight. The word laser comes from a phrase that describes howit works: light amplification by stimulated emission ofradiation. Light amplification means that the light isstrengthened. Stimulated emission means that the atomsemit light when exposed to electromagnetic radiation.
  2. 2. HOW CAN LASER LIGHT BE USEDLasercan beused forhair notto grow
  3. 3. HOW DOES A LASERPRODUCE LASER LIGHT?•A helium-neon laser is shown at the bottom of the slide.•The laser tube contains a mixture of helium and neon gases.•An electric current causes this gas mixture to emit photons.•You may recall that a photon is a packet of light energy.•The mirrors at both ends of the tube reflect the photons back and forth.• As a photon travels back and forth, it may bump into a neon particle. This causes the neonparticle to emit a photon with the same energy as the one that caused the collision.•Then the two photons travel together in step with one another.•This process continues until there is a stream of in-step photons traveling up and down thetube.•Some of the light “leaks” through the partially reflecting mirror.•This light is the laser beam.
  4. 4. HOW IS LASER LIGHT DIFFERENT AND STRONGER THANREGULAR WHITE LIGHT?Laser light is very coherent. This means that the wavesleaving the laser remain in phase for a very long time. Lightfrom a flashlight is not coherent. As a result, a laser canproject a distinct beam of light much farther than aflashlight.Laser light is almost monochromatic. Because it is created byexciting a specific substance to emit photons, the light emittedby the source is almost all one specific wavelength. The lightfrom a flashlight contains all of the colors in the spectrum, Laser light is directional. This means that theforming "white light". beam of light being emitted does not spread much with distance. Hence it can still appear as a point of light many meters away from the source. A flashlight beam will quickly spread the further it is viewed from the source.
  5. 5. IS LASER LIGHT DANGEROUS•A laser is "concentrated light" in that its light of pretty much onefrequency and focused in a tight beam.•And if this light is directed into someones eyes, damage to the retina canresult.•In higher power lasers, we find applications where they can inscribediamonds or cut all kinds of things, including metal.• If a laser beam can cut through a thick metal plate, it can cut throughflesh with ease.•A laser this powerful could take off a limb.•Directed at the eye, it would destroy the eye in an instant.•Spaces where lasers are being used require that warning signs be postedand that individuals working there wear appropriate eye protection.•Divergence from safety procedures can result in serious injury.
  6. 6. HOW CAN WE PROTECT OUR EYES FROM LASER LIGHT?•wearing laser safety glasses or goggles can protect the eyes from the risks that lasers pose.•These laser safety glasses and goggles provide protection from reflected laser light and direct beamexposure.•It is recommended that you find out the class of the laser you are working with as well as the appropriatewavelength range to ensure the best possible protection.•We can’t emphasize enough how important it is to protect your eyes and yourself from the harmful effectsof laser radiation.•Remember, the damage done to the eyes from laser radiation exposure can be permanent!