The level of training shall be appropriate to the level of the laser hazard being used. LSS provides general laser safety training that is to be supplemented by specific in-lab training by the Responsible Faculty Member or experienced user designated by the Responsible Faculty Member to provide training.
- Class 1 and 2 – training not required
- Class 1M and 2M – application dependent, contact the LSS
- Class 3a and 3R – training not required
- Class 3b and 4 – training is required
Refresher training is required every two years.
Basics
The word LASER is an acronym for Light Amplification by Stimulated Emission of Radiation. Lasers are used as research tools in many programmes at Sabanci University.
In this document, the word laser will be limited to electromagnetic radiation-emitting devices using light amplification by stimulated emission of radiation at wavelengths from 180 nanometers (nm) to 1 millimeter (mm). The electromagnetic spectrum includes energy ranging from gamma rays to radiofrequency. Figure 14.1 illustrates the total electromagnetic spectrum and wavelengths of the various regions.
The lasers used at Sabanci University include the ultraviolet, visible and infrared regions of the spectrum. Ultraviolet radiation for lasers consists of wavelengths between 180 and 400 nm. The visible region consists of radiation with wavelengths between 400 and 700 nm. This is the portion we call visible light. The infrared region of the spectrum consists of radiation with wavelengths between 700 nm and 1 mm.
A laser generates a beam of very intense light. The major difference between laser light and light generated by white light sources (such as a light bulb) is that laser light is monochromatic, directional and coherent. Monochromatic means that all of the light produced by the laser is of a single wavelength. White light is a combination of all visible wavelengths (400 - 700 nm). Directional stands for the beam of light with very low divergence.
The color or wavelength of light being emitted depends on the type of lasing material being used.
Figure 14.1 Electromagnetic Spectrum (Courtesy of UIUC) |
Table 14.1 illustrates various types of material currently used for lasing and the wavelengths that are emitted by that type of laser. Note that certain materials and gases are capable of emitting more than one wavelength. The wavelength of the light emitted in this case is dependent on the optical configuration of the laser.
Coherent means that the waves of light are in phase with each other. A light bulb produces many wavelengths, making it incoherent.
| Table 14.1 Common Laser Classifications by Wavelength | |
|---|---|
| Type | Wavelength (nm) |
| Ultraviolet (180-400 nm) | |
| Argon Fluoride(ArF) | 193 |
| Krypton Chloride(KrCl) | 222 |
| Krypton Fluoride(KrF) | 249 |
| Xenon-Chloride(XeCl2) | 308 |
| Nitrogen(N2) | 337 |
| Helium-Cadmium(HeCd) | 325 |
| Visible (400-700 nm) | |
| Helium-Neon(He-Ne) | 543, 594, 612,633 |
| Krypton(Kr) | 647 |
| Ruby | 694 |
| Argon(Ar) | 468 to 515 |
| Nd; YAG(second harmonic generation) | 532 |
| Infrared (700 nm to 1 μm) | |
| Galium-Arsenide(diode) | 850 |
| Carbon dioxide(CO2) | 10600 |
| Nd; YAG | 1064 |
| Ho; YAG | 2100 |