F O U N DAT I O N S O F T E C H N O LO GY

AN INTRODUCTION TO OPTICAL TECHNOLOGY

UNIT3.9

OBJECTIVES

• Demonstrate three methods of controlling light.• Explain how controlled light is useful to humans.• Describe the function and application of lasers.

3WAYS TO CONTROL LIGHT

• Block it with something.• Reflect it.• Bend it.

WHY DO WE CARE ABOUT CONTROLLING LIGHT?

WHY DO WE CARE ABOUT CONTROLLING LIGHT?

• Our eyes• Eyeglasses and contact lenses• Lenses for TV, movies, and cameras• Copy machines/fax machines• Binoculars and telescopes• Microscopes and magnifiers• Overhead projectors• CD/DVD players• Weather and spy satellites• Medical devices

WHAT IS WHITE LIGHT?

WHAT IS WHITE LIGHT?

• White light is regular light from the sun or a bulb. It contains all of the colors of the rainbow.

CAN LIGHT BE SPLIT?

CAN LIGHT BE SPLIT?

• Yes, you can split light into its colors with a prism.

WHAT IS A LASER?

WHAT IS A LASER?

• A laser is a special source of light that is only one pure color. Laser light can not be split into the colors of the rainbow.

WHAT ARE SOME SPECIAL ATTRIBUTES OF LASERS?

WHAT ARE SOME SPECIAL ATTRIBUTES OF LASERS?

• Focus-Lasers can be focused on a very small spot and can shine for long distances without spreading out much.

• Energy-The spot contains a lot of energy-so much energy that some lasers can cut through thick metal, and smaller ones can be used as scalpels.

• Communications-Lasers can send out a lot of information through long threads of glass (fiber optics).A single laser can send thousands of phone conversations through a fiber at the same time.

• Holograms-Lasers are used to make 3-D pictures called holograms.