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Laser Pointers

Lasers are commonly available for use as pointers for teaching and lecturing purposes and are recommended as a low power, safer substitute for high power laser beam alignment.

Laser pointers with a range of radiant power outputs are available which usually fall into Class 1, Class 2 or Class 2M. Class 1 laser pointers are normally safe. Class 2 and 2M pointers are not hazardous under usual conditions of use however they can cause harm to the eyes particularly if the beam is stared into or observed through optical instruments which magnifying and or focus. Normally the eye’s blink reflex affords protection to short duration accidental exposure to Class 2 and 2M lasers.

Either Class 1 or Class 2 lasers pointers are the recommended choice where a laser pointer is necessary. Class 3R or 3B laser pointers must not be used for teaching and lecturing purposes.

Laser pointers are available which emit red light (wavelengths between 630 and 740 nm) or green light (532 nm). The response of the human eye is wavelength dependent, peaking at 550nm and tailing off at wavelengths higher and lower than 550nm. Because green light has a wavelength closer than red light to the eye’s peak response point, a relatively lower radiant power of green light will produce adequate visual stimulus compared with red light. Whilst this would seem to favour selection of a green light rather than a red light pointer there are counter arguments. Firstly, green light pointers may cause after images and ‘comet trail’ effects in people viewing the beam projected onto a screen, secondly, green beams can sometimes consist of pulses of light with high peak power per pulse giving a misleading indication of the risk, and thirdly there may be other invisible laser beams emitted at different wavelengths in addition to green beams at 532nm.

Therefore laser pointers emitting red light are recommended.

Laser pointers to be used for University purposes should be acquired from University approved suppliers, to ensure they originate from a reliable source. The power output from lasers pointers from unreliable sources can be significantly higher than claimed and above the power output threshold for the claimed laser class. This creates risk not only of eye damage but of none compliance with the Artificial Optical Radiations Regulations 2010. Laser pointers should be labeled with the correct laser Class category label.

Laser pointers should only be used as a pointing device and should be securely stored when not in use. Persons who use laser pointers should ensure that they are aware of the potential hazards and should comply with the basic instructions below.

 


DO

  • Follow the manufacturer’s instructions.
  • Take care when operating the laser pointer.

 

DO NOT

  • Do not keep the ‘on’ button depressed continuously.
  • Do not point the laser beam in the direction of other people.
  • Do not point the laser beam at any mirrored surface.
  • Never look directly into the beam / beam aperture when on.
  • Never allow unauthorised use.
  • Do not modify laser pointers in any way.


RECOMMENDED

  • Only acquire pointers originating from reliable manufacturers.
  • Select red light pointers in preference to green light.
  • Check the power output before use and that the pointer is correctly labelled; contact the University Laser Safety Officer for advice.