Laser Diode

Introduction to Laser Diode

The term laser stands for light amplification by stimulated emission of radiation.  Laser light is monochromatic, which means that it consists of a single color and not a mixture of colors.  Laser light is also called coherent light, a single wavelength, as compared to incoherent light, which consists of a wide band of wavelengths.  The laser diode normally emits coherent light, whereas the LED emits incoherent light.

The basic symbol of a laser diode is shown below.

A pn junction is formed by two layers of doped gallium arsenide.  The length of the pn junction bears a precise relationship with the wavelength of the light to be emitted.

Symbol of Laser Diode

 

laser diode,what is laser diode,symbol of laser diode,applications of laser diode

Symbol of Laser Diode

An application of laser Diode

Laser diode and photo diodes are used in the pick-up system of compact disk (CD) players. Audio information (sound) is digitally recorded in stereo on the surface of a compact disk in the form of microscopic “pits” and “flats.”  A lens arrangement focuses the laser beam from the diode onto the CD surface.  As the CD rotates, the lens and beam follow the track under control of a servomotor.  The laser light, which is altered by the pits and flats along the recorded track, is reflected back from the track through a lens and optical system to infrared photodiodes.  The signal from the photodiodes is then used to reproduce the digitally recorded sound.

Comments are closed.

x
Sign up for our Newsletter

Enter your email and stay on top of things,