Three types of devices interact with light:
● Light-detection devices
● Light-conversion devices
● Light-emitting devices
The semiconductor material and the doping tech- niques used determine the relevant light wavelength of a particular device.
Basic Principles of light
light is electromagnetic radiation that is visible to the human eye. Light is thought to travel in a form similar to radio waves. Like radio waves, light is measured in wavelengths.
Light travels at 186,000 miles per second, or 30,000,000,000 centimeters per second, through a vacuum. The velocity is reduced as it passes through various types of mediums. The frequency range of light is 300 to 300,000,000 gigahertz (giga 5 1,000,000,000). Of this frequency range, only a small band is visible to the human eye. The visible region spans from approximately 400,000 to 750,000 gigahertz. Infrared light falls below 400,000 gigahertz, and ultraviolet light lies above 750,000 gigahertz. Light waves at the upper end of the frequency range have more energy than light waves at the lower end.
Questions
1. What is light?
2. What frequency range of light is visible to the human eye?
3. What is infrared light?
4. What is ultraviolet light?
What type of light wave has the most energy