Diode-pumped solid state laser
Solid-state lasers based on pumping a solid gain medium, for example a crystal with a laser diode. Common laser crystals are neodymium-doped Yttrium aluminium garnet (Nd:YAG) or neodymium-doped Yttrium Lithium Fluoride (Nd:(LiYF4). or Nd:YLF).
Laser diode modules
Laser diode modules ar based on laser diodes. In this type of laser the active medium is a semiconductor which is pumped by injected electric current. The modules contains beam shaping optics and a stabilization to make the diode laser useful for optical applications. Very common is a single mode fiber coupling that provides an excellent beam quality.
He-Ne laser
The helium–neon laser or He-Ne laser, belongs to the gas lasers. The active medium is a mixture of helium and neon inside of a small bore capillary tube surrounded by a larger tube as gas reservoir. It is pumped by a high DC voltage that causes a gas discharge. The He-Ne laser is manufactured for more than 50 years without major design changes.
Ar-Ion laser
The Argon-Ion laser is a gas laser which uses an ionized gas as its active medium. Like the He-Ne laser it is pumped by a gas discharge. Argon ion lasers have the advantage of emitting a variety of wavelength in one collinear beam.
Fiber
Fiber in this context is the short form of optical fiber sometimes also called glass fiber. It is an light waveguide made pure glass (silica). A single mode fiber provides a Gaussian like beam profile like a free laser beam.