Laser diode

The laser diode is the most common type of laser produced. 
A laser diode, or LD, is an electrically pumped semiconductor laser.
The active medium in the laser diode is formed by a p-n junction of a semiconductor diode.

Wavelengths of laser diodes and their applications. The wavelength of laser diodes depends on two primary factors, the semiconductor material used in the diode and the optical cavity design. 

405 nm - InGaN blue-violet laser, in Blu-ray Disc and HD DVD drives
473 nm - Nd:YAG Bright blue laser pointers
535 nm - AlGaAs Bright green laser pointers
640 nm - High brightness red laser pointers
657 nm - AlGaInP DVD drives, laser pointers
670 nm - AlGaInP cheap red laser pointers
785 nm - GaAlAs Compact Disc drives
848 nm - GaAs laser mice
1064 nm - AlGaAs fiber-optic communication, DPSS laser pump frequency
1550 nm - InGaAsP, InGaAsNSb fiber-optic communication

Laser Diode Package Type:

Applications Examples:
Fiber optic communications
Barcode readers
Laser pointers
CD/DVD/Blu-ray reading and recording
Laser printing
Scanning and increasingly directional lighting sources

The potential applications for laser diodes are endless. New technologies for laser diodes are being developed daily. They're an active part in the medical, industrial, automotive, defense and other industries. 


MRI Alignment
Tire Alignment Systems
Patient Alignment
PET Scanners
Garment/Apparel Alignment
Plasma Cutting Alignment
Tire Manufacturing for Re-tread Alignment
Automotive Interior Alignment
Chassis Alignment
Cutting Tool/Saw Blade Alignment

Machine Vision (such as industry cameras)

Biomedical/Cell Sampling

Flow Cytometry

Laser skin Therapy

Range Finding (Leupold rangefinders)

Infrared Surveillance (safety cameras at night)


Lumber Scanning

Agricultural Anti-Avian System

Barcode Readers

Laser Induced Fluorescence


3D Modeling

3D Scanning

Blood Analysis

Optical Disc Mastering

Display and Entertainment


Materials Processing


Particle Counting

Low Level Laser Therapy

Laser Measurement

Laser Scanner

Laser Tracker

Non-Contact Measuring Devices

Weapons Simulation and Combat Training

Manufacturing Control and Automation

Laser Measurement

Lumber Sorting

Pollution Monitoring and Measuring

Fluid Measurement and Analysis

Information Input (Touch Screens)


Laser Sight

Research and Development

Laser Sensing

List of laser applications at Wikipedia: Many scientific, military, medical and commercial laser applications have been developed since the invention of the laser in 1958. The coherency, high monochromaticity, and ability to reach extremely high powers are all properties which allow for these specialized applications.