Monday, August 3, 2009

REVISION MODULE 7: LIGHT & OPTICAL SYSTEM

OBJECTIVES:

  1. Identify the main components of a laser.
  2. state the types of laser.
  3. state the characteristics of the laser light.
  4. explain optical systems that use laser light in the field of engineering, medicine and industry.

INTRODUCTION:

  • Laser light is a form of light which seen as a beam of light.
  • Laser is a short form for "LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION"
  • Laser is a device or instrument that produces thin beams of light. Observe the picture below.

1.0 MAIN COMPONENTS OF A LASER.


Four main components of a laser:
  1. active medium
  2. -optical cavity or medium which made of gas, liquid or solid.

  3. excitation mechanism
    -flash-lamp supply energy that excites the electrons of atoms.

  4. feedback mechanism
  5. -consists of two mirrors which reflec atoms back and forth through the active medium so that the light can be further amplified.

  6. output coupler

-allows a portion of the laser light and leave the laser on the form of a beam.

Diagram below shows the stages in production of laser light:

2.0 TYPES OF A LASER.

•Helium-Neon Laser
•Ruby Laser
•Carbon dioxide laser
•Argon laser
•Neodynium-YAG laser
•Dye laser

Types of laser are determine by the laser substance used in each of the system.


3.0 CHARACTERISTICS OF THE LASER LIGHT.

The properties of lase light:
  1. monochromatic - single wavelenghts or one colour)
  2. coherent- laser light moves in phases with the other.
  3. very directional- laser light is a very strong and concentrated beam which travels in straight line.

4.0 USES OF LASER LIGHT.

In medicine:
  1. dentistry
  2. remove birthmarks
  3. eye surgery
  4. endoscope

In engineering:

  1. lavelling tool
  2. construction of tunnels
  3. road surface profiling

In communication:

  1. optical fibre use in telecomunication system such as telephone conversation, computer connections and television channels.

In industry:

  1. the bar code scanner system.
  2. a laser printer.

In entertainment:

  1. used in CD or DVD player.
  2. laser light show.

In education:

  1. laser pointer
  2. as educational aides

In manufacturing:

  1. laser cutting machine.
  2. laser welding system.

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