Lasers

Lasers are devices that produce intense beams of monochromatic, coherent radiation. The word “laser” is an acronym for Light Amplification by Stimulated Emission of Radiation. Lasers consist of a gain medium inside an optical cavity, and are available in a variety of types for numerous purposes. Types of lasers include carbon dioxide lasers (CO2 lasers), dye lasers, excimer lasers, helium cadmium lasers (HeCd lasers), helium neon lasers (HeNe lasers), laser diodes, laser pointers, and solid state lasers. 

Carbon dioxide lasers and dye lasers are available from many suppliers. Carbon dioxide lasers or CO2 lasers use energy-state transitions between vibrational and rotational states of CO2 molecules to long infrared (IR) wavelengths. They can maintain continuous levels of power. CO2 lasers are used in cutting, welding, etching, and marking applications. Dye lasers use a dye solution as an active medium. They have an output of short-pulse, broad spectrum content with an achievable gain.

Excimer lasers, helium cadmium lasers, and helium neon lasers are also available. Excimer lasers are rare-gas, metal-vapor lasers that produce wide beams of ultraviolet (UV) laser light. Excimer lasers operate through the electronic transition of molecules. Helium cadmium lasers or HeCD lasers are economical, continuous-wave sources for violet and UV outputs. They lasers are used for holographs and 3D stereolithography applications. Helium neon lasers and HeNe lasers maintain emissions that are determined by neon atoms by way of resonant transfers of helium excitation. These lasers operate continuously in the red, infrared, and far-integrated regions while emitting highly monochromatic radiation.

Other types of lasers include laser diodes, laser pointers, and solid state lasers. Laser diodes are also known as diode lasers. These devices use light emitting diodes (LED) to produce stimulated emissions in the form of coherent light output. Laser pointers are compact instruments that produce a visible, low-power laser light. Solid state lasers are lasers that use transparent substances, such as crystalline or glass, as the active medium. These substances are doped to provide the necessary energy states for lasing. Solid state lasers are used in both high and low power applications.

Lasers differ in terms of output, wavelength, and features. The output may be continuous, pulsed, or Q-switched, depending on the application. In addition to the output, lasers produce a range of colored wavelengths. Laser wavelengths are available in UV, violent, blue, green, yellow, orange, red, and infrared. Each color represents a different wavelength range and is measured in nanometers. Some lasers are equipped with additional features such as packaging of multiples (arrays), fiber pig tailing, an internal power supply, polarized output, and thermoelectric cooling. Additional features for lasers may be available from some laser manufactures.