Purpose And Requirements

This guide presents a summary of the basics of laser safety, biological effects, and exposure limits to be used at Sabancı University. This guide applies to all laser classes (1 to 4). Some recommendations will improve laser safety in the laboratory. Because of the wide variety of lasers and laser uses that are possible, this guide provides performance based goals rather than prescriptive requirements.

Responsibilities

Each laser user is responsible for the operational safety of the device. This includes applicable recommendations of the position and termination of all beams and reflections, using appropriate entryway controls, and using appropriate eye protection. Laser users shall not bypass or defeat entryway safety features, barriers, or interlocks. Doing so is a serious safety violation and may lead to loss of laser use privileges.

Standards

The international and national resources for laser applications and safety are given below:

  • TS EN 60825-4/A1 - Safety of laser products - Part 4: Laser guards
  • TS-EN-60825-1 - Safety of laser products - Part 1: Equipment classification and requirements (IEC 60825-1:2014)
  • ANSI Z136 Standards (Laser Institute of America)

Training

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.

Figure 14.1 Electromagnetic Spectrum  (Courtesy of UIUC)

Figure 14.1 Electromagnetic Spectrum (Courtesy of UIUC)

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.

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 Fluorid(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

Listen