The Argon laser was invented in 1964 by William Bridges at Hughes Aircraft and is one of a family of Ion lasers that use a noble gas as the active medium. This laser is used in many applications such as:
This image shows all the wavelengths
of light emmitted by the Argon laser operating in multi-mode. Every wavelength
is a monochromatic light source of itself and each wavelength has a very narrow
bandwidth. The two dominant wavelengths, of 514nm "Green" and 488nm
"Blue" make up about 67% of the total beam output power. Single line operation
is also possible by inserting prisms, diffraction gratings and other optical
devices to "filter out" the unwanted wavelengths. Of course, when single line
operation is required, the total output power decreases dramatically as well.
The laser resonator is made up
of two mirrors. One is highly reflective (HR) and other is a partially reflective
mirror (OC). From this optic (the Output Coupler) the beam emerges as laser light.
The Brewster's Angle optic mounted at both ends of the tube, minimizes reflection
loses while creating a polarized beam. When the laser is first turned on, a delay
allows for temperature stabilization. Then a pulse of high voltage (8 kilovolts DC)
ionizes the argon gas. Upon ionization, high DC current (45 Amps) and about 600 volts
DC across the tube maintains a sufficient discharge to keep the gas ionized.
The typical Argon laser tube has a tungsten bore which has a high melting point
and allows the laser to operate at higher power levels with longer tube life.
Argon lasers with average powers of over three watts require tap water cooling and separate three phase 220 AC volt @ 50 Amps per phase electrical line feeds.
Safety Note:
Argon laser emmissions are hazardous to view. Both diffuse and direct exposures
beyond the applicable MPE (Maximum Permissable Exposure) limit can cause permanent
damage to the retina.
ITL // 25.10.1996