May 8 2013
A helium–neon laser or HeNe laser is a gas laser consisting of a mixture of neon and helium within a small bore capillary tube, which is excited by a DC electrical discharge. It was the first gas laser invented by Javan et al in 1962 at Bell Telephone Laboratories. It operates continuously in the red, infrared and far-infrared regions. However, the most widely used HeNe laser operates at a wavelength of 632.8 nm in the red part of the visible spectrum.
The process of producing He and Ne in specific excited states is known as pumping. In He-Ne laser, pumping occurs through collision of electrons and atoms during an electrical discharge. The 632.8 nm optical light is emitted by the laser when the Neon atoms decay from an excited state to an ordinary state. The light emitted by the He-Ne laser is extremely monochromatic, unidirectional, spatially coherent and aligned to be parallel to the body of the laser.
Red HeNe lasers have a number of industrial and scientific uses. They are commonly used in laboratory demonstrations in the field of optics due to their ease of operation and relatively low cost.
Laser Properties
| Laser Properties |
| Laser type |
Gas |
| Pump source |
Electrical discharge |
| Operating Wavelengths |
| 623.8 nm |
| 543.5 nm |
| 593.5 nm |
| 611.8 nm |
| 1.1523 µm |
| 1.52 µm |
| 3.3913 µm |
Applications
He-Ne laser is used widely in commercial and industrial applications, and commonly used in laboratory demonstrations of optics. It is the most common laser used in holography.
Other major applications of He-Ne laser include:
- Barcode scanners
- Tool alignment
- Non-contact measuring and monitoring
- Blood analysis
- Particle counting and food sorting
- Alignment of high power CO2 and YAG treatment lasers and pointing beams.