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
-optical cavity or medium which made of gas, liquid or solid.


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


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


4. 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.