What is a Laser Diodes? | Opto Electronics

What is a Laser Diodes

Overview of laser diodes

What is a laser?

This is actually an acronym for "Light Amplification by Stimulated Emission of Radiation".
Basically, this means increasing the amplitude of light by induced emission.

The difference between laser diodes and light emitting diodes (LEDs)

Both laser diodes and LEDs are formed through the creation of a PN semiconductor junction. When an electrical current is supplied a positive hole, which has a positive charge, and an electron, which has a negative charge, bond, emitting light.

Since an LED operates by spontaneous emission, the phase is not uniform. A laser diode, on the other hand, operates by induced emission, meaning that the phase of the light is uniform. Its particular characteristics are based on the underlying theory that the amplitude of light can increased as it travels back and forth within a resonator, making it possible to obtain large optical outputs.

Therefore, a laser diode, in contrast with an LED, generates coherent or "arrayed" light using a lens, which can be sent long distances or focused on an extremely small point. In addition, faster operation is possible compared with LEDs, enabling widespread use in more disparate fields.

(For application examples, see below)

Laser Diode Features and Applications

Sample applications that use features of lasers (light whose phase is in phase) are shown below. Additional uses, such as projector light sources and heating of minute areas, are also possible.

	Characteristics	Function	Application Examples
①	Allows accurate pointing via pin spot illumination	Illumination	Laser microscopes, laser scalpels, pointing markers, and the like
②	Enables high-speed reading of minute signals with micron spots	Reading	Optical disk reading / writing (CDs, DVDs)
③	Attenuation over distance is low, allowing for far transmission	Measurements	Road distance / building height measurements, for example.
④	High-speed modulation is possible, making it possible to transmit large amounts of information	Communications	Optical communications in PCs, mobile phones, and other equipment.
⑤	Interference fringes are easily created, enabling detection of minute changes	Sensors	Sensor devices such as fire alarms, dust control, and laser mice.