Ion laser
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An ion laser is a gas laser that uses an ionized gas as its lasing medium.[1] Like other gas lasers, ion lasers feature a sealed cavity containing the laser medium and mirrors forming a
Types
Krypton laser
A krypton laser is an ion laser using ions of the
Krypton lasers can emit visible light close to several different wavelengths, commonly 406.7 nm, 413.1 nm, 415.4 nm, 468.0 nm, 476.2 nm, 482.5 nm, 520.8 nm, 530.9 nm, 568.2 nm, 647.1 nm, and 676.4 nm.
Argon laser
The argon-ion laser was invented in 1964 by William Bridges at the Hughes Aircraft Company[2] and it is one of the family of ion lasers that use a noble gas as the active medium.
Argon-ion lasers are used for
Common argon and krypton lasers are capable of emitting continuous-wave (CW) output of several milliwatts to tens of watts. Their tubes are usually made from nickel end bells, kovar metal-to-ceramic seals, beryllium oxide ceramics, or tungsten disks mounted on a copper heat spreader in a ceramic liner. The earliest tubes were simple quartz, then followed by quartz with graphite disks. In comparison with the helium–neon lasers, which require just a few milliamperes of input current, the current used for pumping the argon laser is several amperes, since the gas has to be ionized. The ion laser tube produces much waste heat, and such lasers require active cooling.
The typical noble-gas ion-laser plasma consists of a high-current-density glow discharge in a noble gas in the presence of a magnetic field. Typical continuous-wave plasma conditions are current densities of 100 to 2000 A/cm2, tube diameters of 1.0 to 10 mm, filling pressures of 0.1 to 1.0 Torr (0.0019 to 0.019 psi), and an axial magnetic field of the order of 1000 gauss.[4]
Other commercially available types
- Ar/Kr: A mix of argon and krypton can result in a laser with output wavelengths that appear as white light.
- Helium–cadmium: blue laser emission at 442 nm and ultraviolet at 325 nm.
- Copper vapor: yellow and green emission at 578 nm and 510 nm.
Experimental
Applications
- Confocal laser scanning microscopy
- Surgical
- Laser medicine
- High-speed typesetters
- Laser-light shows
- DNA sequencers
- Spectroscopy experiments
- Pumping dye lasers[8]
- Semiconductor wafer inspection
- Direct write high density PCB lithography
- Fiber Bragg Gratingproduction
- Long coherence length models can be used for holography.
See also
References
- ^ W. B. Bridges, "LASER OSCILLATION IN SINGLY IONIZED ARGON IN THE VISIBLE SPECTRUM", Appl. Phys. Lett. 4, 128–130 (1964).
- ^ "Lexel Laser is under construction".
- ^ Bridges, Halstead et al., Proceedings of the IEEE, 59 (5). pp. 724–739.
- ^ Hoffman Toschek, et al., "The Pulsed Xenon Ion Laser: Covers the UV, visible, and near-IR with optics changes", IEEE Journal of Quantum Electronics
- ^ Hattori, Kano, Tokutome and Collins, "CW Iodine Ion Laser in a Positive Column Discharge", IEEE Journal of Quantum Electronics, June 1974
- ^ Cold Cathode Pulsed Gas Laser" by R. K. Lomnes and J. C. W. Taylor in: Review of Scientific Instruments, vol 42, no. 6, June, 1971.
- ^ F. J. Duarte and L. W. Hillman (Eds.), Dye Laser Principles (Academic, New York, 1990) Chapters 3 and 5